CVE-2026-2454: Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to handle incorrectly reported array lengths which allows malicious user to…

PriorityP347high8.6CVSS 3.1

AVNACLPRNUINSCCNINAH

EPSS

0.27%

19.5th percentile

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to handle incorrectly reported array lengths which allows malicious user to cause OOM errors and crash the server via sending corrupted msgpack frames within websocket messages to calls plugin. Mattermost Advisory ID: MMSA-2025-00537

Affected

6 ranges

Vendor	Product	Version range	Fixed in
mattermost	mattermost	10.11.0 – 10.11.10	—
mattermost	mattermost	11.2.0 – 11.2.2	—
mattermost	mattermost	11.3.0 – 11.3.0	—
mattermost	mattermost_server	>= 10.11.0 < 10.11.11	10.11.11
mattermost	mattermost_server	>= 11.2.0 < 11.2.3	11.2.3
mattermost	mattermost_server	>= 11.3.0 < 11.3.1	11.3.1

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