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jackson-databind — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2026-83557

DefaultBaseTypeLimitingValidator is the PolymorphicTypeValidator applied automatically whenever @JsonTypeInfo is used without an explicitly configured custom validator. It denies polymorphic resolution only for a fixed set of "unsafe base types", and its isSafeSubType method returns true unconditionally for every base type outside that set. java.lang.Comparable was absent from the list despite being implemented by a very large fraction of JDK and application classes, comparable in breadth to java.io.Serializable, which is on the list for that reason. An application declaring an @JsonTypeInfo-annotated property or class with Comparable as its base type, and no custom PolymorphicTypeValidator, will accept a type identifier for essentially any class implementing Comparable. This yields an attacker-controlled object instantiation primitive; a demonstrated case constructs a java.io.File for an arbitrary attacker-chosen path, which becomes path-traversal-adjacent if the application subsequently calls path-sensitive methods on the value. No class implementing Comparable has been identified that yields code execution through deserialization alone. Global Default Typing via activateDefaultTyping is not affected, because that method structurally requires an explicit PolymorphicTypeValidator argument. This affects com.fasterxml.jackson.core:jackson-databind from 2.11.0 before 2.18.10, from 2.19.0 before 2.21.6, and from 2.22.0 before 2.22.2, and tools.jackson.core:jackson-databind from

Products
jackson-databind
Affected versions
2.14.0+ds-1, 2.14.0+ds-1+deb13u1, 2.14.0+ds-2, 2.14.0+ds-3, 2.14.0-1, 2.14.0-1+deb12u1, 2.18.11-1
Fixed versions
2.18.11-1
CVEs
CVE-2026-83557
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 08:53 UTC · Revision 1

Source evidence

DEBIAN-CVE-2026-83557

core-osv · Original source

Published 1 Sept 2026, 15:17 UTC

DefaultBaseTypeLimitingValidator is the PolymorphicTypeValidator applied automatically whenever @JsonTypeInfo is used without an explicitly configured custom validator. It denies polymorphic resolution only for a fixed set of "unsafe base types", and its isSafeSubType method returns true unconditionally for every base type outside that set. java.lang.Comparable was absent from the list despite being implemented by a very large fraction of JDK and application classes, comparable in breadth to java.io.Serializable, which is on the list for that reason. An application declaring an @JsonTypeInfo-annotated property or class with Comparable as its base type, and no custom PolymorphicTypeValidator, will accept a type identifier for essentially any class implementing Comparable. This yields an attacker-controlled object instantiation primitive; a demonstrated case constructs a java.io.File for an arbitrary attacker-chosen path, which becomes path-traversal-adjacent if the application subsequently calls path-sensitive methods on the value. No class implementing Comparable has been identified that yields code execution through deserialization alone. Global Default Typing via activateDefaultTyping is not affected, because that method structurally requires an explicit PolymorphicTypeValidator argument. This affects com.fasterxml.jackson.core:jackson-databind from 2.11.0 before 2.18.10, from 2.19.0 before 2.21.6, and from 2.22.0 before 2.22.2, and tools.jackson.core:jackson-databind from

osv:DEBIAN-CVE-2026-83557

jackson-databind

Fixed versions: Not specified

jackson-databind

Fixed versions: Not specified

jackson-databind

Fixed versions: 2.18.11-1

Complete source record
{
  "id": "d777ea42449aac8824c667f5c6a97f07ea3d901fa72c767471860e12717dc5bf",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-83557",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-83557",
    "summary": "DefaultBaseTypeLimitingValidator is the PolymorphicTypeValidator applied automatically whenever @JsonTypeInfo is used without an explicitly configured custom validator. It denies polymorphic resolution only for a fixed set of \"unsafe base types\", and its isSafeSubType method returns true unconditionally for every base type outside that set. java.lang.Comparable was absent from the list despite being implemented by a very large fraction of JDK and application classes, comparable in breadth to java.io.Serializable, which is on the list for that reason. An application declaring an @JsonTypeInfo-annotated property or class with Comparable as its base type, and no custom PolymorphicTypeValidator, will accept a type identifier for essentially any class implementing Comparable. This yields an attacker-controlled object instantiation primitive; a demonstrated case constructs a java.io.File for an arbitrary attacker-chosen path, which becomes path-traversal-adjacent if the application subsequently calls path-sensitive methods on the value. No class implementing Comparable has been identified that yields code execution through deserialization alone. Global Default Typing via activateDefaultTyping is not affected, because that method structurally requires an explicit PolymorphicTypeValidator argument. This affects com.fasterxml.jackson.core:jackson-databind from 2.11.0 before 2.18.10, from 2.19.0 before 2.21.6, and from 2.22.0 before 2.22.2, and tools.jackson.core:jackson-databind from ",
    "evidence": "osv:DEBIAN-CVE-2026-83557",
    "products": [
      {
        "name": {
          "value": "jackson-databind",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.14.0+ds-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.14.0+ds-2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.14.0+ds-3",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.14.0-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.14.0-1+deb12u1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.18.11-1",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "jackson-databind",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.14.0+ds-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.14.0+ds-1+deb13u1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.14.0+ds-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.14.0+ds-3",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.18.11-1",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "jackson-databind",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.18.11-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "2.14.0+ds-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.14.0+ds-2",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.14.0+ds-3",
            "evidence": "/affected/2/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "DEBIAN-CVE-2026-83557",
      "aliases": [
        "DEBIAN-CVE-2026-83557"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "jackson-databind",
            "purl": "pkg:deb/debian/jackson-databind?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "versions": [
            "2.14.0+ds-1",
            "2.14.0+ds-2",
            "2.14.0+ds-3",
            "2.14.0-1",
            "2.14.0-1+deb12u1",
            "2.18.11-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-83557.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "jackson-databind",
            "purl": "pkg:deb/debian/jackson-databind?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "2.14.0+ds-1",
            "2.14.0+ds-1+deb13u1",
            "2.14.0+ds-2",
            "2.14.0+ds-3",
            "2.18.11-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-83557.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.18.11-1"
                }
              ]
            }
          ],
          "package": {
            "name": "jackson-databind",
            "purl": "pkg:deb/debian/jackson-databind?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "2.14.0+ds-1",
            "2.14.0+ds-2",
            "2.14.0+ds-3"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-83557.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-20T04:00:07.342422376Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-83557"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-83557"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-83557",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 377332,
  "published_at": "2026-09-01T15:17:37.987+00:00"
}