CVE-2025-55070: Mattermost · Missing Authentication for Critical Functionality
Affects MattermostSource GCVE Database
Not known to be exploited · CVSS 6.5 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 | 6.5 |
|---|
- Patch
- Available – fixed in 11
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/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 vulnerability is fixed. No other mitigation is indicated or required according to the available data.
Description
CVE-2025-55070 is a vulnerability in Mattermost versions prior to 11 where multi-factor authentication is not enforced on WebSocket connections. This flaw allows unauthenticated users to access sensitive information through WebSocket events. The issue is addressed in Mattermost version 11.