CVE-2025-12689 MEDIUM

CVE-2025-12689: DoS in Calls plugin via malformed UTF-8 in WebSocket request

Vendor Mattermost
Product Mattermost
Weakness CWE-1287
Published December 17, 2025
Last update December 17, 2025
View on NVD All CVEs

CVSS base score

6.5/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

December 17, 2025 CVE published
December 17, 2025 Record updated