CVE-2026-16049

Published: Aug 17, 2026Modified: Aug 18, 2026

4.3

Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Exploitability: 2.8 / Impact: 1.4

Source: responsibledisclosure@mattermost.com (Secondary)

Description

Mattermost Plugins versions <=11.8 10.20.11 11.5.7.0 _The Mattermost GitLab plugin fails to verify channel permissions when processing API requests with a caller-supplied_ {{post_id}}_, and fails to validate the_ {{web_url}} _parameter against the configured GitLab instance, which allows an authenticated attacker to inject bot-authored messages containing arbitrary URLs into channels they do not have access to via the_ {{createIssue}} _and_ {{attachCommentToIssue}} _API endpoints._ Mattermost Advisory ID: MMSA-2026-00673

Related CWEs

CWE-862

Missing Authorization

The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

References (1)

https://mattermost.com/security-updates

Source: responsibledisclosure@mattermost.com

Timeline

No history available yet.