What is CVE-2026-13411?

CVE-2026-13411 is a medium-severity vulnerability in Mattermost, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 4.3/10. Published 2026-10-22.

How severe is CVE-2026-13411?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in Mattermost

CVE-2026-13411

Mattermost versions 11.7.x <= 11.7.11 fail to validate null elements when decoding playbook import conditions which allows an authenticated attacker to crash the Playbooks plugin instance-wide via a crafted import request containing a null condition. Mattermost Advisory ID: MMSA-2026-00709

Published 2026-10-22 · last modified 2026-10-22.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Mattermost

Weakness classification (CWE)

CWE-754 — Improper Check for Unusual or Exceptional Conditions

References

mattermost.com/security-updates (vendor-advisory)

Frequently asked questions

What is CVE-2026-13411?: CVE-2026-13411 is a medium-severity vulnerability in Mattermost, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 4.3/10. Published 2026-10-22.
How severe is CVE-2026-13411?: Medium severity. CVSS v3 base score is 4.3 out of 10.