CVE-2025-11776: Mattermost · Incorrect Authorization
Affects MattermostSource GCVE Database
Not known to be exploited · CVSS 4.3 Medium : upgrade to 11 when convenient.
Data as of 13 Nov 2026, 18:45 UTC
Thin evidence
One scorer or none| CNA (Mattermost) | CVSS 3.1 | 4.3 |
|---|
- Patch
- Available – fixed in 11
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 14 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
Upgrade Mattermost to 11.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mattermost Mattermost | Affected
| Fixed in
|
AI-suggested
Upgrade Mattermost to version 11 or later, where this authorization issue is fixed. No additional mitigation is required once the official fix is applied.
Description
CVE-2025-11776 is an authorization vulnerability in Mattermost versions prior to 11. It allows guest users to access the archived channel search API endpoint, enabling them to discover archived public channels without proper authorization. The issue is fixed in Mattermost version 11.