CVE-2025-54888

Summary

Fedify is a TypeScript library for building federated server apps powered by ActivityPub. In versions below 1.3.20, 1.4.0-dev.585 through 1.4.12, 1.5.0-dev.636 through 1.5.4, 1.6.0-dev.754 through 1.6.7, 1.7.0-pr.251.885 through 1.7.8 and 1.8.0-dev.909 through 1.8.4, an authentication bypass vulnerability allows any unauthenticated attacker to impersonate any ActivityPub actor by sending forged activities signed with their own keys. Activities are processed before verifying the signing key belongs to the claimed actor, enabling complete actor impersonation across all Fedify instances. This is fixed in versions 1.3.20, 1.4.13, 1.5.5, 1.6.8, 1.7.9 and 1.8.5.

Affected Software

VendorProductVersion RangeStatus
fedify-devfedify< 1.3.20affected
fedify-devfedify>= 1.4.0-dev.585, < 1.4.13affected
fedify-devfedify>= 1.5.0-dev.636, < 1.5.5affected
fedify-devfedify>= 1.6.0-dev.754, < 1.6.8affected
fedify-devfedify>= 1.7.0-pr.251.885, < 1.7.9affected
fedify-devfedify>= 1.8.0-dev.909, < 1.8.5affected

Weaknesses

  • CWE-287: CWE-287: Improper Authentication
  • CWE-863: CWE-863: Incorrect Authorization

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: yes
    • Technical Impact: partial

References