Medium 6.5Published Jan 8, 2026

CVE-2026-22246Local Mastodon users can enumerate and access severed relationships of every other local user

Updated under an hour ago (Oct 26, 2026, 2:50 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for mastodon

Exploited in the last 30 days

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon 4.3 added notifications of severed relationships, allowing end-users to inspect the relationships they lost as the result of a moderation action. The code allowing users to download lists of severed relationships for a particular event fails to check the owner of the list before returning the lost relationships. Any registered local user can access the list of lost followers and followed users caused by any severance event, and go through all severance events this way. The leaked information does not include the name of the account which has lost follows and followers. This has been fixed in Mastodon v4.3.17, v4.4.11 and v4.5.4.

CVSS: 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Weakness (CWE): CWE-201
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jan 8, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

mastodon mastodon mastodon:mastodon (from the name)	before 4.3.17; from 4.4.0-beta.1, < 4.4.11; from 4.5.0-beta.1, < 4.5.4	CNA record
joinmastodon mastodon joinmastodon:mastodon	before 4.3.17; from 4.4.0 before 4.4.11; from 4.5.0 before 4.5.4	NVD

References

References

https://github.com/mastodon/mastodon/security/advisories/GHSA-ww85-x9cp-5v24	x-refsource-confirm, third-party-advisory
https://github.com/mastodon/mastodon/commit/68e30985ca7afdb89af1b2e9dc962e1993dc8076	x-refsource-misc, patch
https://github.com/mastodon/mastodon/commit/b2bcd34486fd6681cc0f30028086ef0f47282adf	x-refsource-misc, patch
https://github.com/mastodon/mastodon/commit/c1fb6893c5175d74c074f6f786d504c8bc610d57	x-refsource-misc, patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.