CVE-2025-41423: Mattermost Server

Medium severity, CVSS 4.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.10 fail to properly validate permissions for the API endpoint /plugins/playbooks/api/v0/signal/keywords/ignore-thread, allowing any user or attacker to delete posts containing actions created by the Playbooks bot, even without channel access or appropriate permissions.

Affected products

• Mattermost Mattermost Server: from 9.11.0, before 9.11.11 (fixed in 9.11.11); from 10.4.0, before 10.4.3 (fixed in 10.4.3); version 10.5.0 only

Published 2025-04-24. Last modified 2026-06-17.