CVE-2026-5139

MEDIUM EPSS 6.6%
Published Jun 22, 20261w ago · Modified Jun 23, 20261w ago
5.4 CVSS 3.1
Medium
Find Similar
Published Jun 22, 2026 1w ago
Last Modified Jun 23, 2026 1w ago

Description

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

CVSS Details

Base Score
5.4
Exploitability
2.8
Impact
2.5
Vector string
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

Threat Intelligence

EPSS Exploit Probability
6.6% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-862 Missing Authorization Authorization

Affected Products 4

VendorProductVersionRange
mattermostmattermost_server*≥10.11.0  –  <10.11.18
mattermostmattermost_server*≥11.5.0  –  <11.5.6
mattermostmattermost_server*≥11.6.0  –  <11.6.3
mattermostmattermost_server*≥11.7.0  –  <11.7.1

References 1

  • mattermost.com https://mattermost.com/security-updates
    Vendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.