CVE-2026-3116

MEDIUM 4.9CVE-2026-3116 · Published 26/03/2026 · updated 17/06/2026

In short

CVE-2026-3116 is a MEDIUM (CVSS 4.9) vulnerability affecting mattermost server (mattermost).
Chance of exploitation in the next 30 days (EPSS): 0.36%, higher than 29.5% of all vulnerabilities.
Fix: update to 10.11.12, 11.2.4, 11.3.2, 11.4.1 or later.

Package	Affected versions	Patched versions
mattermost server mattermost	`≥ 10.11.0, < 10.11.12≥ 11.2.0, < 11.2.4≥ 11.3.0, < 11.3.2≥ 11.4.0, < 11.4.1`	`10.11.1211.2.411.3.211.4.1`

Description

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

References

mattermost.com/security-updates · Vendor Advisory

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Package

Affected versions

Patched versions

mattermost server

mattermost

≥ 10.11.0, < 10.11.12≥ 11.2.0, < 11.2.4≥ 11.3.0, < 11.3.2≥ 11.4.0, < 11.4.1

10.11.1211.2.411.3.211.4.1

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