CVE-2026-42462

Summary

Fedify is a TypeScript library for building federated server apps powered by ActivityPub. Prior to versions 1.9.11, 1.10.10, 2.0.18, 2.1.14, and 2.2.3, an attacker can make use of JSON-LD features to restructure a JSON-LD document that would change how Fedify interprets it without changing its Linked Data Signature, allowing them to alter a third-party signed activity they have received. Versions 1.9.11, 1.10.10, 2.0.18, 2.1.14, and 2.2.3 fix the issue.

Affected Software

VendorProductVersion RangeStatus
fedify-devfedify>= 2.2.0, < 2.2.3affected
fedify-devfedify>= 2.1.0, < 2.1.14affected
fedify-devfedify>= 2.0.0, < 2.0.18affected
fedify-devfedify>= 1.10.0, < 1.10.10affected
fedify-devfedify< 1.9.11affected

Weaknesses

  • CWE-180: CWE-180: Incorrect Behavior Order: Validate Before Canonicalize
  • CWE-347: CWE-347: Improper Verification of Cryptographic Signature
  • CWE-436: CWE-436: Interpretation Conflict
  • CWE-1289: CWE-1289: Improper Validation of Unsafe Equivalence in Input

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References