What is CVE-2026-96260?

CVE-2026-96260 is a medium-severity vulnerability in Mattermost, classified under CWE-789. CVSS score: 6.5/10. Published 2026-09-22.

How severe is CVE-2026-96260?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Mattermost

CVE-2026-96260

Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to enforce a request body size limit during CSRF validation of plugin requests which allows an authenticated user to exhaust server memory and cause a denial of service via a large request body sent to a plugin endpoint.. Mattermost Advisory ID: MMSA-2026-00775

Published 2026-09-22.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

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-789

References

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

Frequently asked questions

What is CVE-2026-96260?: CVE-2026-96260 is a medium-severity vulnerability in Mattermost, classified under CWE-789. CVSS score: 6.5/10. Published 2026-09-22.
How severe is CVE-2026-96260?: Medium severity. CVSS v3 base score is 6.5 out of 10.