Mastodon streaming API fails to disconnect disabled and suspended users

published 2025-10-13 12 mo ago modified 2026-10-19 20 d ago also BIT-mastodon-2025-62175 , EUVD-2025-34112 , GHSA-r2fh-jr9c-9pxh

cvss: 4.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits: 0; none known

Mastodon is a free, open-source social network server based on ActivityPub. In versions before 4.4.6, 4.3.14, and 4.2.27, disabling or suspending a user account does not disconnect the account from the streaming API. This allows disabled or suspended accounts to continue receiving real-time updates through existing streaming connections and to establish new streaming connections, even though they cannot interact with other API endpoints. This undermines moderation actions, as administrators expect disabled or suspended accounts to be fully disconnected from the service. This issue has been patched in versions 4.4.6, 4.3.14, and 4.2.27. No known workarounds exist.

Patch / fix

fixed in 2 links 1

bitnami mastodon 4.2.27, 4.3.14, 4.4.6
joinmastodon mastodon 4.2.27, 4.3.14, 4.4.6

github.com/mastodon/mastodon@2971ac9 commit

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 12 mo ago (2025-10-14)

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
OSV	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem	package	affected	fixed in
bitnami	mastodon	<4.2.27 >=4.3.0, <4.3.14 >=4.4.0, <4.4.6	4.2.27 4.3.14 4.4.6

Affected products

mastodon mastodon

Classification

Weakness

CWE-273 Improper Check for Dropped Privileges
CWE-274 Improper Handling of Insufficient Privileges

References

github.com /mastodon/mastodon/commit/2971ac9863b91372e68ac152caf6f4dbff511d17
patch
github.com /mastodon/mastodon/security/advisories/GHSA-r2fh-jr9c-9pxh
vendor-advisory, advisory
nvd.nist.gov /vuln/detail/CVE-2025-62175
web

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary