CVE-2026-5139
Analyzed
Analyzed - Analysis Complete
Authorization Bypass in Mattermost GitLab Integration
Vulnerability report for CVE-2026-5139, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-06-22
Last updated on: 2026-06-23
Assigner: Mattermost, Inc.
Description
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 Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| mattermost | mattermost_server | From 10.11.0 (inc) to 10.11.18 (exc) |
| mattermost | mattermost_server | From 11.7.0 (inc) to 11.7.1 (exc) |
| mattermost | mattermost_server | From 11.5.0 (inc) to 11.5.6 (exc) |
| mattermost | mattermost_server | From 11.6.0 (inc) to 11.6.3 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-862 | The product does not perform an authorization check when an actor attempts to access a resource or perform an action. |
