SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-3109

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.

LOW 2.2EPSS 0.29%

Does this matter?

Lower severity and a low EPSS score (0.29%). Track it; it rarely justifies an emergency change on its own.

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

CVSS 3.1
2.2 LOWCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L
EPSS
0.29% probability · 22th percentile
CISA KEV
Not listed
Weakness
CWE-754
Affected
mattermost/mattermost server
Source
responsibledisclosure@mattermost.com

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.