🛡️ CVE-2026-2454 — mattermost-server

🟡 CVSS 5.8 — Medium ✅ No Known Exploit CWE-1287 NVD
5.8
CVSS Score
0 Low4 Medium7 High9 Critical10

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

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality none, integrity none, availability low.

Weakness class

CVE-2026-2454 is classified as CWE-1287: Improper Validation of Specified Type of Input. 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.

Affected software

CVE-2026-2454 is recorded against 1 package.

  • mattermost-server (from 11.3.0 up to 11.3.1)

Timeline and source

Published on 16 March 2026 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

mattermost.com

Details

Severity MEDIUM
CVSS Score 5.8
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
CWE CWE-1287
Public Exploit ✅ No
Source NVD
Published 2026-03-16
Updated 2026-08-11
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
mattermost-server 11.3.0 11.3.1

References

Similar Threats

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