CVE-2025-54888

@fedify/fedify: Improper Authentication and Incorrect Authorization

State: Published
Severity: 8.7 High
Published: Aug 9, 2025
Updated: Feb 4, 2026
Reserved: Jul 31, 2025

Description

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.

Scores

CVSS	Score	Vector	Source
4.0	8.7 High	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-287 Improper Authentication
CWE-863 Incorrect Authorization

Affected Products

Product	Versions
fedifyfedify-dev	< 1.3.20Affected >= 1.4.0-dev.585, < 1.4.13Affected >= 1.5.0-dev.636, < 1.5.5Affected >= 1.6.0-dev.754, < 1.6.8Affected >= 1.7.0-pr.251.885, < 1.7.9Affected >= 1.8.0-dev.909, < 1.8.5Affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.