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Improper Authentication

CVE-2025-54888

High
8.7/10

Summary

Fedify is a TypeScript library for building federated server apps powered by ActivityPub. In versions prior to 1.3.20, 1.4.x prior to 1.4.13, 1.5.x prior to 1.5.5, 1.6.x prior to 1.6.8, 1.7.x prior to 1.7.9 and 1.8.x prior to 1.8.5-pr.360.1336, 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.

  • LOW
  • NETWORK
  • NONE
  • NONE

CWE-287 - Improper Authentication

Improper (or broken) authentication attacks are widespread, and have accounted for many of the worst data breaches in recent years. Improper authentication attacks are a class of vulnerabilities where an attacker impersonates a legitimate user by exploiting weaknesses in either session management or credential management to gain access to the user’s account. This can result in disclosure of sensitive information, and can lead to system compromise, theft, identity theft, and fraud.

References

Advisory Timeline

  • Published