CVE-2025-12689

DoS in Calls plugin via malformed UTF-8 in WebSocket request

State: Published
Severity: 6.5 Medium
Published: Dec 17, 2025
Updated: Dec 17, 2025
Reserved: Nov 4, 2025

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.

Scores

CVSS	Score	Vector	Source
3.1	6.5 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H	Mattermost

Weaknesses

CWE-1287 Improper Validation of Specified Type of Input

Affected Products

Product	Versions
MattermostMattermost	11.0.0 through 11.0.4Affected 10.12.0 through 10.12.2Affected 10.11.0 through 10.11.6Affected 11.1.0Not affected 11.0.5Not affected 10.12.3Not affected 10.11.7Not affected

References

https://mattermost.com/security-updates

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