CVE-2026-5139
GitLab Plugin Allows Non-Admin Users to Modify Default Instance Configuration
CVSS Score
5.4
EPSS Score
0.0%
EPSS Percentile
0th
Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler, which allows any authenticated user to overwrite the global default GitLab instance configuration via the {{/gitlab connect <instance-name>}} slash command.. Mattermost Advisory ID: MMSA-2026-00644
| CWE | CWE-862 |
| Vendor | mattermost |
| Product | mattermost |
| Published | Jun 22, 2026 |
| Last Updated | Jun 22, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
Low
Affected Versions
Mattermost / Mattermost
11.7.0 ≤ 11.7.0 11.6.0 ≤ 11.6.2 11.5.0 ≤ 11.5.5 10.11.0 ≤ 10.11.17
Credits
hunterxluxhug