Vulnerability-Lookup

UBUNTU-CVE-2026-91776 (CVE-2026-91776)

Vulnerability from osv_ubuntu – Published: 2026-09-23 03:17 – Updated: 2026-09-23 03:17 – Source website

Details

TypeDeserializerBase._findDeserializer() in FasterXML jackson-databind caches the resolved deserializer under the raw, attacker-supplied type ID. When name-based polymorphism is configured with a fallback, for example @JsonTypeInfo(use = Id.NAME, defaultImpl = ...), every distinct unrecognized type ID resolves to the same fallback deserializer but is retained as its own key in the _deserializers map. That map has no configurable bound and lives for the lifetime of the type deserializer, so an attacker who can repeatedly supply fresh unknown type IDs causes monotonic memory retention across requests. The reporter observed 10,000 retained entries from 10,000 distinct unknown IDs, against a single entry for a control that repeated one unknown ID the same number of times, isolating attacker-controlled key cardinality from request volume. Exploitation requires an application that enables name-based polymorphism with a defaultImpl or equivalent fallback, accepts attacker-influenced type IDs, and reuses a long-lived ObjectMapper across requests. The fix stops caching fallback resolutions for unrecognized IDs and bounds both the number of cached entries and the length of a cacheable type ID.

Severity

7.5 (High)


                    
                      CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-91776	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-91776	REPORT
	https://github.com/FasterXML/jackson-databind/sec…	REPORT
	https://github.com/FasterXML/jackson-databind/pull/6203	REPORT
	https://github.com/FasterXML/jackson-databind/iss…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libjackson2-databind-java",
            "binary_version": "2.2.2-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "jackson-databind",
        "purl": "pkg:deb/ubuntu/jackson-databind@2.2.2-1ubuntu0.1~esm1?arch=source\u0026distro=esm-infra-legacy/trusty"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.2.2-1",
        "2.2.2-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libjackson2-databind-java",
            "binary_version": "2.4.2-3ubuntu0.1~esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "jackson-databind",
        "purl": "pkg:deb/ubuntu/jackson-databind@2.4.2-3ubuntu0.1~esm2?arch=source\u0026distro=esm-apps/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.4.2-2",
        "2.4.2-3",
        "2.4.2-3ubuntu0.1~esm1",
        "2.4.2-3ubuntu0.1~esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libjackson2-databind-java",
            "binary_version": "2.9.8-1~18.04"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "jackson-databind",
        "purl": "pkg:deb/ubuntu/jackson-databind@2.9.8-1~18.04?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.8.6-1",
        "2.9.1-1",
        "2.9.4-1",
        "2.9.5-1",
        "2.9.8-1~18.04"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libjackson2-databind-java",
            "binary_version": "2.10.2-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "jackson-databind",
        "purl": "pkg:deb/ubuntu/jackson-databind@2.10.2-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.9.9.3-1",
        "2.10.0-2",
        "2.10.1-1",
        "2.10.2-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libjackson2-databind-java",
            "binary_version": "2.13.0-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "jackson-databind",
        "purl": "pkg:deb/ubuntu/jackson-databind@2.13.0-2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.12.1-1",
        "2.12.5-1",
        "2.13.0-1",
        "2.13.0-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libjackson2-databind-java",
            "binary_version": "2.14.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "jackson-databind",
        "purl": "pkg:deb/ubuntu/jackson-databind@2.14.0-1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.14.0-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libjackson2-databind-java",
            "binary_version": "2.14.0+ds-1build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "jackson-databind",
        "purl": "pkg:deb/ubuntu/jackson-databind@2.14.0+ds-1build1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.14.0+ds-1",
        "2.14.0+ds-1build1"
      ]
    }
  ],
  "aliases": [],
  "details": "TypeDeserializerBase._findDeserializer() in FasterXML jackson-databind caches the resolved deserializer under the raw, attacker-supplied type ID. When name-based polymorphism is configured with a fallback, for example @JsonTypeInfo(use = Id.NAME, defaultImpl = ...), every distinct unrecognized type ID resolves to the same fallback deserializer but is retained as its own key in the _deserializers map. That map has no configurable bound and lives for the lifetime of the type deserializer, so an attacker who can repeatedly supply fresh unknown type IDs causes monotonic memory retention across requests. The reporter observed 10,000 retained entries from 10,000 distinct unknown IDs, against a single entry for a control that repeated one unknown ID the same number of times, isolating attacker-controlled key cardinality from request volume. Exploitation requires an application that enables name-based polymorphism with a defaultImpl or equivalent fallback, accepts attacker-influenced type IDs, and reuses a long-lived ObjectMapper across requests. The fix stops caching fallback resolutions for unrecognized IDs and bounds both the number of cached entries and the length of a cacheable type ID.",
  "id": "UBUNTU-CVE-2026-91776",
  "modified": "2026-09-23T03:17:00Z",
  "published": "2026-09-23T03:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-91776"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-91776"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-wv8q-qhhj-9h54"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/FasterXML/jackson-databind/pull/6203"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/FasterXML/jackson-databind/issues/6203"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-91776"
  ]
}

CVE-2026-91776 (GCVE-0-2026-91776)

Vulnerability from cvelistv5 – Published: 2026-09-23 02:17 – Updated: 2026-09-23 14:03

Title

jackson-databind: unbounded growth of the type id cache in TypeDeserializerBase retains every unknown raw type ID

Summary

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-23 14:02 UTC

CWE

CWE-400 - Uncontrolled Resource Consumption

Assigner

HeroDevs mitre root

References

2 references

URL	Tags
https://github.com/FasterXML/jackson-databind/sec…	vendor-advisory
https://github.com/FasterXML/jackson-databind/iss…	patch

Impacted products

2 products

Vendor	Product	Version
FasterXML	jackson-databind	Affected: 2.0.0 , ≤ 2.18.10 (maven) Affected: 2.19.0 , ≤ 2.21.6 (maven) Affected: 2.22.0 , ≤ 2.22.2 (maven)
FasterXML	jackson-databind	Affected: 3.0.0 , ≤ 3.1.6 (maven) Affected: 3.2.0 , ≤ 3.2.2 (maven)

Credits

Daniel Birtwhistle (dabirt)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-91776",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-23T14:02:42.582789Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-23T14:03:16.129Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-wv8q-qhhj-9h54"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://repo1.maven.org/maven2",
          "defaultStatus": "unaffected",
          "packageName": "com.fasterxml.jackson.core:jackson-databind",
          "product": "jackson-databind",
          "programRoutines": [
            {
              "name": "com.fasterxml.jackson.databind.jsontype.impl.TypeDeserializerBase._findDeserializer"
            }
          ],
          "repo": "https://github.com/FasterXML/jackson-databind",
          "vendor": "FasterXML",
          "versions": [
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              "status": "affected",
              "version": "2.0.0",
              "versionType": "maven"
            },
            {
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              "status": "affected",
              "version": "2.19.0",
              "versionType": "maven"
            },
            {
              "lessThanOrEqual": "2.22.2",
              "status": "affected",
              "version": "2.22.0",
              "versionType": "maven"
            }
          ]
        },
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          "defaultStatus": "unaffected",
          "packageName": "tools.jackson.core:jackson-databind",
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            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Daniel Birtwhistle (dabirt)"
        }
      ],
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          "lang": "en",
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              "value": "\u003cp\u003eTypeDeserializerBase._findDeserializer() in FasterXML jackson-databind caches the resolved deserializer under the raw, attacker-supplied type ID. When name-based polymorphism is configured with a fallback, for example @JsonTypeInfo(use = Id.NAME, defaultImpl = ...), every distinct unrecognized type ID resolves to the same fallback deserializer but is retained as its own key in the _deserializers map. That map has no configurable bound and lives for the lifetime of the type deserializer, so an attacker who can repeatedly supply fresh unknown type IDs causes monotonic memory retention across requests. The reporter observed 10,000 retained entries from 10,000 distinct unknown IDs, against a single entry for a control that repeated one unknown ID the same number of times, isolating attacker-controlled key cardinality from request volume. Exploitation requires an application that enables name-based polymorphism with a defaultImpl or equivalent fallback, accepts attacker-influenced type IDs, and reuses a long-lived ObjectMapper across requests. The fix stops caching fallback resolutions for unrecognized IDs and bounds both the number of cached entries and the length of a cacheable type ID.\u003c/p\u003e"
            }
          ],
          "value": "TypeDeserializerBase._findDeserializer() in FasterXML jackson-databind caches the resolved deserializer under the raw, attacker-supplied type ID. When name-based polymorphism is configured with a fallback, for example @JsonTypeInfo(use = Id.NAME, defaultImpl = ...), every distinct unrecognized type ID resolves to the same fallback deserializer but is retained as its own key in the _deserializers map. That map has no configurable bound and lives for the lifetime of the type deserializer, so an attacker who can repeatedly supply fresh unknown type IDs causes monotonic memory retention across requests. The reporter observed 10,000 retained entries from 10,000 distinct unknown IDs, against a single entry for a control that repeated one unknown ID the same number of times, isolating attacker-controlled key cardinality from request volume. Exploitation requires an application that enables name-based polymorphism with a defaultImpl or equivalent fallback, accepts attacker-influenced type IDs, and reuses a long-lived ObjectMapper across requests. The fix stops caching fallback resolutions for unrecognized IDs and bounds both the number of cached entries and the length of a cacheable type ID."
        }
      ],
      "metrics": [
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          "cvssV3_1": {
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            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
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        "shortName": "HeroDevs"
      },
      "references": [
        {
          "name": "GHSA-wv8q-qhhj-9h54",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-wv8q-qhhj-9h54"
        },
        {
          "name": "FasterXML/jackson-databind#6203",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/FasterXML/jackson-databind/issues/6203"
        }
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            }
          ],
          "value": "Where the polymorphic shape allows it, avoid defaultImpl or another catch-all fallback for name-based type resolution so that unrecognized type IDs fail rather than resolving, or restrict accepted type IDs with a custom TypeIdResolver that rejects unknown names before resolution. Shortening ObjectMapper or type deserializer lifetime limits accumulation but does not eliminate it."
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "36c7be3b-2937-45df-85ea-ca7133ea542c",
    "assignerShortName": "HeroDevs",
    "cveId": "CVE-2026-91776",
    "datePublished": "2026-09-23T02:17:50.480Z",
    "dateReserved": "2026-09-15T01:22:24.203Z",
    "dateUpdated": "2026-09-23T14:03:16.129Z",
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  },
  "dataType": "CVE_RECORD",
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

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UBUNTU-CVE-2026-91776 (CVE-2026-91776)

CVE-2026-91776 (GCVE-0-2026-91776)

Tags

Sightings

Nomenclature

Related by attack behaviour