What is CVE-2026-2454?

CVE-2026-2454 is a medium-severity vulnerability in Mattermost, classified under CWE-1287. CVSS score: 5.8/10. Published 2026-03-16.

How severe is CVE-2026-2454?

Medium severity. CVSS v3 base score is 5.8 out of 10.

Vulnerability in Mattermost

CVE-2026-2454

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…

EPSS: 0.001 (31.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L.

Affected products

Mattermost — versions 11.3.0, 11.2.0, 10.11.0

Weakness classification (CWE)

CWE-1287

References

MMSA-2025-00537 (vendor-advisory)

Frequently asked questions

What is CVE-2026-2454?: CVE-2026-2454 is a medium-severity vulnerability in Mattermost, classified under CWE-1287. CVSS score: 5.8/10. Published 2026-03-16.
How severe is CVE-2026-2454?: Medium severity. CVSS v3 base score is 5.8 out of 10.