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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-23961 Detail

Description

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon allows server administrators to suspend remote users to prevent interactions. However, some logic errors allow already-known posts from such suspended users to appear in timelines if boosted. Furthermore, under certain circumstances, previously-unknown posts from suspended users can be processed. This issue allows old posts from suspended users to occasionally end up on timelines on all Mastodon versions. Additionally, on Mastodon versions from v4.5.0 to v4.5.4, v4.4.5 to v4.4.11, v4.3.13 to v4.3.17, and v4.2.26 to v4.2.29, remote suspended users can partially bypass the suspension to get new posts in. Mastodon versions v4.5.5, v4.4.12, v4.3.18 are patched.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/mastodon/mastodon/releases/tag/v4.3.18 GitHub, Inc.
https://github.com/mastodon/mastodon/releases/tag/v4.4.12 GitHub, Inc.
https://github.com/mastodon/mastodon/releases/tag/v4.5.5 GitHub, Inc.
https://github.com/mastodon/mastodon/security/advisories/GHSA-5h2f-wg8j-xqwp GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-863 Incorrect Authorization GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-23961
NVD Published Date:
01/21/2026
NVD Last Modified:
01/21/2026
Source:
GitHub, Inc.