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[ CVE-2026-91777 · Published 23 Sep 2026 ]

jackson-databind quadratic forward-reference completion

CVSS 7.5 EPSS <1%3 agency advisoriesFix available

[ Why it matters ]Priority signals

  • Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official description

Forward-reference completion for @JsonIdentityInfo object IDs in FasterXML jackson-databind performs a linear scan of the pending-reference accumulator for every resolved ID. The affected paths are CollectionDeserializer.CollectionReferringAccumulator.resolveForwardReference() and the equivalent implementation in MapDeserializer. When a document first creates N unresolved object-ID references in an identity-enabled collection or map and then defines those same IDs in reverse order, completion performs on the order of N * (N + 1) / 2 identity comparisons, so a shallow document whose size grows linearly causes quadratic CPU work during deserialization. The reporter instrumented equals() calls on the ID class and measured exactly 2,003,000 comparisons at N = 2,000, against zero comparisons in the pending-reference lookup path for an equally sized control in which every reference was already resolved. The input requires no deep nesting and no syntactically unusual JSON. Exploitation requires an application that deserializes attacker-influenced JSON into an identity-enabled collection or map. The fix replaces the repeated linear lookup with a keyed pending-reference structure.

[ Fixes ]Fixes and patches

[ Advisories ]Government CERT advisories

  • CERT-FRCERTFR-2026-AVI-1336

    Multiple vulnerabilities in IBM products Translated from French

    Multiple vulnerabilities have been discovered in IBM products. Some of them allow an attacker to cause remote arbitrary code execution, privilege escalation and remote denial of service.

    CVE-2026-14671CVE-2026-11548CVE-2022-22950+490 more CVEs
  • CERT-FRCERTFR-2026-AVI-1249

    Multiple vulnerabilities in VMware products Translated from French

    Multiple vulnerabilities have been discovered in VMware products. They allow an attacker to cause a security problem not specified by the vendor.

    CVE-2026-75595CVE-2026-53910CVE-2026-56404+288 more CVEs
  • BSI CERT-BundWID-SEC-2026-3665

    SOS GmbH JobScheduler: Multiple vulnerabilities allow an unspecified attack Translated from German

    CVE-2026-19032CVE-2026-59889CVE-2026-9563+7 more CVEs

[ Packages ]Affected open-source packages

  • com.fasterxml.jackson.core:jackson-databind mavenAffected >= 2.19.0, <= 2.21.6 · fixed in 2.21.7 · GHSA-cxp5-3px4-pw24
  • tools.jackson.core:jackson-databind mavenAffected >= 3.0.0, <= 3.1.6 · fixed in 3.1.7 · GHSA-cxp5-3px4-pw24
  • tools.jackson.core:jackson-databind mavenAffected >= 3.2.0, <= 3.2.2 · fixed in 3.2.3 · GHSA-cxp5-3px4-pw24
  • com.fasterxml.jackson.core:jackson-databind mavenAffected >= 2.5.0, <= 2.18.10 · fixed in 2.18.11 · GHSA-cxp5-3px4-pw24
  • com.fasterxml.jackson.core:jackson-databind mavenAffected >= 2.22.0, <= 2.22.2 · fixed in 2.22.3 · GHSA-cxp5-3px4-pw24

[ References ]References