CVE-2025-54888Public exploitNetwork attack vector

Actor impersonation via late signing-key ownership check

Published Aug 9, 2025 · Updated Feb 4, 2026

Authentication bypass in affected Fedify releases through 1.8.4 allows remote attackers to impersonate actors via forged activities. handleInboxInternal calls routeActivity before doesActorOwnKey verifies that the HTTP signing key belongs to the claimed actor, so a mismatched activity is processed or queued before rejection. No authentication or user interaction is required; attackers can publish messages and change federation relationships as another actor, without reported confidentiality or availability impact.

CVSS severity8.7
High
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in affected Fedify releases through 1.8.4 allows remote attackers to impersonate actors via forged activities. handleInboxInternal calls routeActivity before doesActorOwnKey verifies that the HTTP signing key belongs to the claimed actor, so a mismatched activity is processed or queued before rejection. No authentication or user interaction is required; attackers can publish messages and change federation relationships as another actor, without reported confidentiality or availability impact.

The record

CVE
CVE-2025-54888
Published
Aug 9, 2025
Updated
Feb 4, 2026
Vendor
Fedify
Product
Fedify
Classifications
CWE-287, CWE-863, T1656
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 9, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.3.20
  2. Affected versionversion=>= 1.4.0-dev.585, < 1.4.13
  3. Affected versionversion=>= 1.5.0-dev.636, < 1.5.5
  4. Affected versionversion=>= 1.6.0-dev.754, < 1.6.8
  5. Affected versionversion=>= 1.7.0-pr.251.885, < 1.7.9
  6. Affected versionversion=>= 1.8.0-dev.909, < 1.8.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fedify · Fedifyversion=< 1.3.20; version=>= 1.4.0-dev.585, < 1.4.13; version=>= 1.5.0-dev.636, < 1.5.5; version=>= 1.6.0-dev.754, < 1.6.8; version=>= 1.7.0-pr.251.885, < 1.7.9; version=>= 1.8.0-dev.909, < 1.8.5

Published CVSS scores

8.7GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
CWE-863Incorrect Authorization
T1656Impersonation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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