Medium severity · published May 18, 2026
CVE-2026-3117
Instance and webhook GitLab plugin commands were able to be run by non-admin users
6.5
CVSS
0.2%
EPSS
No
On KEV
Description
Mattermost Plugins versions <=11.5 11.1.5 10.13.11 11.3.4.0 fail to properly check for permissions when processing commands in the Gitlab plugin which allows normal users to uninstall instances or setup webhook connections via the {{gitlab instance {option}}} or the {{/gitlab webhook {option}}} commands. Mattermost Advisory ID: MMSA-2026-00600
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 14% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MA
Mattermost · Mattermost
through 11.1.5; through 10.13.11; through 11.3.4 · source: vendor
MS
Mattermost Server · Mattermost
10.13.0 through 10.13.11; 11.1.0 through 11.1.5; 11.3.0 through 11.3.4 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-3117
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-3117
Vendor Advisory
https://mattermost.com/security-updates
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