CVE-2026-2454
DoS in Calls plugin via malformed msgpack in websocket request.
5.8CVSSMEDIUM
Description
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
CVSS Vector Breakdown
Exploitability
AV:NAttack VectorNetwork
AC:LAttack ComplexityLow
PR:NPrivileges RequiredNone
UI:NUser InteractionNone
Scope
S:CScopeChanged
Impact
C:NConfidentialityNone
I:NIntegrityNone
A:LAvailabilityLow
Weaknesses
Affected Products
Exploitability
Official Patch Available
References
Timeline
Published
Mar 16, 2026
Last Updated
Mar 18, 2026
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