CVE-2025-14273: Mattermost Server

High severity, CVSS 8.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Mattermost versions 11.1.x <= 11.1.0, 11.0.x <= 11.0.5, 10.12.x <= 10.12.3, 10.11.x <= 10.11.7 with the Jira plugin enabled and Mattermost Jira plugin versions <=4.4.0 fail to enforce authentication and issue-key path restrictions in the Jira plugin, which allows an unauthenticated attacker who knows a valid user ID to issue authenticated GET and POST requests to the Jira server via crafted plugin payloads that spoof the user ID and inject arbitrary issue key paths. Mattermost Advisory ID: MMSA-2025-00555

Affected products

• Mattermost Mattermost Server: from 10.11.0, before 10.11.8 (fixed in 10.11.8); from 10.12.0, before 10.12.4 (fixed in 10.12.4); from 11.0.0, before 11.0.6 (fixed in 11.0.6); from 11.1.0, before 11.1.1 (fixed in 11.1.1)

Published 2025-12-22. Last modified 2026-06-17.