CVE-2026-3109

LOW 2.2CVE-2026-3109 · Published 26/03/2026 · updated 17/06/2026

In short

CVE-2026-3109 is a LOW (CVSS 2.2) vulnerability affecting mattermost server (mattermost).
Chance of exploitation in the next 30 days (EPSS): 0.30%, higher than 23.0% of all vulnerabilities.
Fix: update to 10.11.12 or later.

Package	Affected versions	Patched versions
mattermost server mattermost	`≥ 10.11.0, < 10.11.12`	`10.11.12`

Description

Mattermost Plugins versions <=11.4 10.11.11.0 fail to validate webhook request timestamps which allows an attacker to corrupt Zoom meeting state in Mattermost via replayed webhook requests. Mattermost Advisory ID: MMSA-2026-00584

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

10.11.12

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