CVE-2025-12689
Medium
Description
Mattermost versions 11.0.x <= 11.0.4, 10.12.x <= 10.12.2, 10.11.x <= 10.11.6 fail to check WebSocket request field for proper UTF-8 format, which allows attacker to crash Calls plug-in via sending malformed request.
SeverityMedium
CVSS6.5
Exploit probability—
Product
Mattermost Server
PublishedDec 17, 2025
First seenDec 17, 2025
Weakness typeCWE-1287CWE-1287
How to fix
Update
- mattermost mattermost_server10.11.7, 10.12.3, 11.0.5 or later
- github.com/mattermost/mattermost-plugin-calls1.11.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mattermost mattermost_server | 10.11.0 ≤ v < 10.11.7, 10.12.0 ≤ v < 10.12.3, 11.0.0 ≤ v < 11.0.5 | 10.11.7, 10.12.3, 11.0.5 |
| github.com/mattermost/mattermost-plugin-callsGo | v < 1.11.0 | 1.11.0 |
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