CVE-2026-22892: Mattermost Server

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

Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to validate user permissions when creating Jira issues from Mattermost posts, which allows an authenticated attacker with access to the Jira plugin to read post content and attachments from channels they do not have access to via the /create-issue API endpoint by providing the post ID of an inaccessible post.. Mattermost Advisory ID: MMSA-2025-00550

Affected products

• Mattermost Mattermost Server: from 10.11.0, before 10.11.10 (fixed in 10.11.10); from 11.0.0, before 11.1.3 (fixed in 11.1.3); from 11.2.0, before 11.2.2 (fixed in 11.2.2)

Published 2026-02-13. Last modified 2026-06-17.