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VulnerabilityPublished

CVE-2025-55074: Mattermost · Improper Validation of Generative AI Output

Affects MattermostSource GCVE Database

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Not known to be exploited · CVSS 3.0 Low.

Data as of 13 Nov 2026, 20:12 UTC

CVSS 3.1 base score
3.0Low
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Mattermost)CVSS 3.13.0
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:N/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 18 Nov 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Mattermost MattermostAffected
  • =10.11.0
  • =10.5.0
  • >=10.5.0 <=10.5.11
  • >=10.11.0 <=10.11.3
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.

References

Community reviews

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