CVE-2026-86348: mattermost server from 10.11.0 (inclusive), before 10.11.23 (exclusive), from 11.7.0 (inclusive), before 11.7.8…

Affected technology

mattermost server · from 10.11.0 (inclusive), before 10.11.23 (exclusive)
mattermost

mattermost server · from 11.7.0 (inclusive), before 11.7.8 (exclusive)
mattermost

mattermost server · from 11.8.0 (inclusive), before 11.8.5 (exclusive)
mattermost

mattermost server · from 11.9.0 (inclusive), before 11.9.1 (exclusive)
mattermost

Mattermost · <=11.9 11.0.9 11.4.8 11.7.7 10.22.11.0 through <=11.9 11.0.9 11.4.8 11.7.7 10.22.11.0
Mattermost

Description’s affected range: versions <=11.9 11.0.9 11.4.8 11.7.7 10.22.11.0 fail to recover from handler panics, 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

An authenticated user can crash the plugin via a post-action request with an unexpected field type. Vendor/CNA’s CVSS 3.1 assessment (base score 4.3/10) rates confidentiality and integrity impact as none; availability impact as low.