PT-2026-25809 · Mattermost · Mattermost

Published 2026-02-13 · Updated 2026-03-17 · CVE-2026-2454

Positive Technologies (AI Summary)

CVSS v3.1

8.6

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Mattermost versions 10.11.0 through 10.11.10 Mattermost versions 11.2.0 through 11.2.2 Mattermost versions 11.3.0

Description The software does not correctly handle array lengths reported within messages sent via WebSockets to the calls plugin. This allows a malicious user to send corrupted msgpack frames, leading to out-of-memory (OOM) errors and potentially crashing the server.

Recommendations Update Mattermost versions prior to 10.11.11. Update Mattermost versions prior to 11.2.3. Update Mattermost versions prior to 11.3.1.

Fix

DoS

Weakness Enumeration

CWE-1287

Related Identifiers

BDU:2026-06559

CVE-2026-2454

Affected Products

Mattermost

References · 6

• https://nvd.nist.gov/vuln/detail/CVE-2026-2454 · Security Note
• https://mattermost.com/security-updates · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2026-2454 · Vendor Advisory
• https://bdu.fstec.ru/vul/2026-06559 · Security Note
• https://twitter.com/VulmonFeeds/status/2033745909264089186 · Twitter Post
• https://twitter.com/CVEnew/status/2033755319721963743 · Twitter Post