CVE-2026-16049 json
_GitLab Plugin allows cross-channel post injection and phishing via missing channel permission checks in issue API endpoints_
published 2026-08-17 2 mo ago modified 2026-08-18 2 mo ago also EUVD-2026-60209
- cvss
- 4.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 22%
- public exploits
- 0
- none known
Summary
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
Patch / fix
- Mattermost Mattermost 10.11.21, 11.7.6, 11.9.0
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2 mo ago
Exploit prediction
0.29% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 3.9 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N |
Affected products
- Mattermost Mattermost
Classification
- Weakness
-
- CWE-862 Missing Authorization
References
-
mattermost.com
/security-updates
vendor-advisory
Sources
- CVE List CVE-2026-16049
- NVD CVE-2026-16049
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