CVE-2025-54888

@fedify/fedify: Improper Authentication and Incorrect Authorization

HIGH

8.7

CVSS Score

Published: August 9, 2025 at 01:31 AM UTC

Updated: June 17, 2026 at 09:40 AM UTC

1 product affected across 1 vendorFedify

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Severity

HIGH8.7

Exploit prediction

EPSS 0.6%

SSVC

PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Fedify · Fedify Dev

60%

v < 1.3.20v < 1.4.13v < 1.5.5v < 1.6.8v < 1.7.9v < 1.8.5

Affected range stops below 1.3.20, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.4.13, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.5.5, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.6.8, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.7.9, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.8.5, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (3)

Source: [email protected]

https://github.com/fedify-dev/fedify/commit/226d9b84dbec52172a70138bba8861454afde42b

x_refsource_CONFIRM

Source: [email protected]

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

x_refsource_MISC

Source: cverecord

https://github.com/fedify-dev/fedify/commit/14a2f8c6d2c3cbc00c3170a86ad3b7b8555c6847

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.7HIGHGitHub_M

Vector?

Quick Info

StatusDEFERRED

CWE

CWE-287CWE-863

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