CVE-2025-54888

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.

Reserved 2025-07-31 | Published 2025-08-09 | Updated 2025-08-09 | Assigner GitHub_M

Problem types

CWE-287: Improper Authentication

CWE-863: Incorrect Authorization

Product status

< 1.3.20
affected

>= 1.4.0-dev.585, < 1.4.13
affected

>= 1.5.0-dev.636, < 1.5.5
affected

>= 1.6.0-dev.754, < 1.6.8
affected

>= 1.7.0-pr.251.885, < 1.7.9
affected

>= 1.8.0-dev.909, < 1.8.5
affected

References

github.com/...fedify/security/advisories/GHSA-6jcc-xgcr-q3h4

github.com/...ommit/226d9b84dbec52172a70138bba8861454afde42b

cve.org (CVE-2025-54888)

nvd.nist.gov (CVE-2025-54888)

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