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.
References (2)
Core 2
Core References
Vendor Advisory x_refsource_confirm
https://github.com/fedify-dev/fedify/security/advisories/GHSA-6jcc-xgcr-q3h4
Scores
CVSS v4
8.7
EPSS
0.0009
EPSS Percentile
24.7%
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
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-287
CWE-863
Status
published
Products (7)
fedify/fedify
0 - 1.3.20npm
fedify-dev/fedify
< 1.3.20
fedify-dev/fedify
>= 1.4.0-dev.585, < 1.4.13
fedify-dev/fedify
>= 1.5.0-dev.636, < 1.5.5
fedify-dev/fedify
>= 1.6.0-dev.754, < 1.6.8
fedify-dev/fedify
>= 1.7.0-pr.251.885, < 1.7.9
fedify-dev/fedify
>= 1.8.0-dev.909, < 1.8.5
Published
Aug 09, 2025
Tracked Since
Feb 18, 2026