CVE-2026-2454 — DoS in Calls plugin via malformed msgpack in websocket request.

CVE-2026-2454

DoS in Calls plugin via malformed msgpack in websocket request. PUBLISHED

Description (CNA)

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 (CNA)

Vendor / product	Versions
Mattermost / Mattermost	affected 11.3.0 through 11.3.0; affected 11.2.0 through 11.2.2; affected 10.11.0 through 10.11.10; unaffected 11.4.0; unaffected 11.3.1; unaffected 11.2.3; unaffected 10.11.11

CWE

CWE-1287

References

https://mattermost.com/security-updates

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.