What is CVE-2026-3116?

CVE-2026-3116 is a medium-severity vulnerability in Mattermost, classified under Uncontrolled Resource Consumption. CVSS score: 4.9/10. Published 2026-03-26.

How severe is CVE-2026-3116?

Medium severity. CVSS v3 base score is 4.9 out of 10.

Resource exhaustion in Mattermost

CVE-2026-3116

Mattermost Plugins versions <=11.4 11.0.4 11.1.3 11.3.2 10.11.11.0 fail to validate incoming request size which allows an authenticated attacker to cause service disruption via the webhook endpoint. Mattermost Advisory ID: MMSA-2026-00589

Vulnerability class: DoS (Denial of Service)

EPSS: 0.000 (4.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.9 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H.

Affected products

Mattermost — versions 0, 11.5.0, 11.4.1

Weakness classification (CWE)

CWE-400 — Uncontrolled Resource Consumption

References

MMSA-2026-00589 (vendor-advisory)

Frequently asked questions

What is CVE-2026-3116?: CVE-2026-3116 is a medium-severity vulnerability in Mattermost, classified under Uncontrolled Resource Consumption. CVSS score: 4.9/10. Published 2026-03-26.
How severe is CVE-2026-3116?: Medium severity. CVSS v3 base score is 4.9 out of 10.