CVE-2026-86348

Medium

Description

Mattermost versions <=11.9 11.0.9 11.4.8 11.7.7 10.22.11.0 fail to recover from handler panics, which allows an authenticated user to crash the plugin via a post-action request with an unexpected field type.. Mattermost Advisory ID: MMSA-2026-00701

SeverityMedium

CVSS4.3

Exploit probability—

Product

Mattermost Server

PublishedSep 14, 2026

First seenSep 14, 2026

Weakness typeCWE-704CWE-704

How to fix

Update

mattermost mattermost_server10.11.23, 11.7.8, 11.8.5, 11.9.1 or later

Vendor advisories

mattermost.com/security-updates

Affected products

Product	Affected versions	Fixed in
mattermost mattermost_server	10.11.0 ≤ v < 10.11.23, 11.7.0 ≤ v < 11.7.8, 11.8.0 ≤ v < 11.8.5, 11.9.0 ≤ v < 11.9.1	10.11.23, 11.7.8, 11.8.5, 11.9.1

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