CVE-2025-12689: mattermost server from 10.11.0 (inclusive), before 10.11.7 (exclusive), from 10.12.0 (inclusive), before 10.12.3…

Affected technology

mattermost server · from 10.11.0 (inclusive), before 10.11.7 (exclusive)
mattermost

mattermost server · from 10.12.0 (inclusive), before 10.12.3 (exclusive)
mattermost

mattermost server · from 11.0.0 (inclusive), before 11.0.5 (exclusive)
mattermost

Mattermost · 11.0.0 through 11.0.4, 10.12.0 through 10.12.2, 10.11.0 through 10.11.6
Mattermost

Description’s affected range: 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

Component: Not specified by the source

Attack conditions (Vendor/CNA, CVSS 3.1): Network (remote) · Low privileges required · No user interaction required

What an attacker can do

Vendor/CNA’s CVSS 3.1 assessment (base score 6.5/10) rates confidentiality and integrity impact as none; availability impact as high. The description does not specify what an attacker can achieve beyond these rated impacts.