CVE-2026-16049 — _GitLab Plugin allows cross-channel post injection and phishing via missing channel permission checks in issue API endpoints_
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_ {{pos…
Published: 2026-08-17 · CVSS: 3.9 · CVSS 3.1
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
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7