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
Metrics
Affected Vendors & Products
References
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| https://mattermost.com/security-updates |
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History
Mon, 17 Aug 2026 16:30:00 +0000
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ssvc
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Mon, 17 Aug 2026 15:45:00 +0000
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Mattermost
Mattermost mattermost |
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Mattermost
Mattermost mattermost |
Mon, 17 Aug 2026 14:45:00 +0000
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| 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 | |
| Title | _GitLab Plugin allows cross-channel post injection and phishing via missing channel permission checks in issue API endpoints_ | |
| Weaknesses | CWE-862 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: Mattermost
Published:
Updated: 2026-08-17T15:26:18.140Z
Reserved: 2026-07-17T09:46:23.992Z
Link: CVE-2026-16049
Updated: 2026-08-17T15:26:14.599Z
Status : Received
Published: 2026-08-17T15:16:54.420
Modified: 2026-08-17T16:16:50.840
Link: CVE-2026-16049
No data.
OpenCVE Enrichment
Updated: 2026-08-17T16:30:06Z