CVE-2026-2454
Received Received - Intake
Out-of-Memory Crash via Malformed Msgpack in Mattermost Websocket

Publication date: 2026-03-16

Last updated on: 2026-03-18

Assigner: Mattermost, Inc.

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
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Meta Information
Published
2026-03-16
Last Modified
2026-03-18
Generated
2026-06-16
AI Q&A
2026-03-16
EPSS Evaluated
2026-06-14
NVD
CVE-2026-2454
Affected Vendors & Products
Showing 3 associated CPEs
Vendor Product Version / Range
mattermost mattermost_server From 10.11.0 (inc) to 10.11.11 (exc)
mattermost mattermost_server From 11.2.0 (inc) to 11.2.3 (exc)
mattermost mattermost_server From 11.3.0 (inc) to 11.3.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-1287 The product receives input that is expected to be of a certain type, but it does not validate or incorrectly validates that the input is actually of the expected type.
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Impact Analysis

The impact of this vulnerability is that an attacker can cause the Mattermost server to crash by triggering out-of-memory errors. This results in a denial of service (DoS) condition, making the service unavailable to legitimate users.

Compliance Impact

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Executive Summary

This vulnerability exists in certain versions of Mattermost (11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10) where the software fails to properly handle incorrectly reported array lengths. A malicious user can exploit this by sending corrupted msgpack frames within websocket messages to the calls plugin, which can cause out-of-memory (OOM) errors and crash the server.

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