CVE-2025-55074: Mattermost · Improper Validation of Generative AI Output
Affects MattermostSource GCVE Database
Not known to be exploited · CVSS 3.0 Low.
Data as of 13 Nov 2026, 20:12 UTC
Thin evidence
One scorer or none| CNA (Mattermost) | CVSS 3.1 | 3.0 |
|---|
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 18 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mattermost Mattermost | Affected
| Fixed in– |
AI-suggested
Until a fix is available, restrict access to the Agents plugin and monitor permissions carefully to limit exposure.
Description
CVE-2025-55074 is a vulnerability in Mattermost versions 10.11.0 through 10.11.3 and 10.5.0 through 10.5.11 where the Agents plugin fails to enforce access permissions properly. This flaw allows unauthorized users to determine when other users have read channels by accessing channel member objects. The vulnerability has a low severity rating and a CVSS score of 3.0.