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CVE-2026-5139

đŸ”ļ medium
🔍 Scan for this CVE
Summary

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 Score
5.4
Medium
EPSS Score
0.2
Exploit Probability
Published Date
2026-06-22
First Seen: 2026-06-25
📊 Relative Risk Intelligence

This CVE is Lower Risk - more severe than 22.8% of all 330,193 vulnerabilities in our database.

#255,023
Below average severity
Severity Percentile
đŸŽ¯ CISA SSVC Assessment Updated: Jun 22, 2026
🔍 Exploitation Status
None
No known exploits
⚙ī¸ Automatable
NO
Requires human interaction
đŸ’Ĩ Technical Impact
Partial
Limited system impact
🏆 Discovered By
hunterxluxhug
SSVC data provided by CISA
Last Modified 2026-06-23
Source NVD 🔗
CVSS Vector 3.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
CWE IDs (Weakness Types)
CWE-862

đŸ“Ļ Affected Products 4

Vendor Product Status Affected Versions
mattermost mattermost_server Affected
> 10.11.0 < 10.11.18
mattermost mattermost_server Affected
> 11.5.0 < 11.5.6
mattermost mattermost_server Affected
> 11.6.0 < 11.6.3
mattermost mattermost_server Affected
> 11.7.0 < 11.7.1

🔗 References 1

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

🔗 Related CVEs 6

CVE ID Severity CVSS EPSS Summary Published
CVE-2026-6062 đŸ”ļ medium 6.4 0.2 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 validate channel o... 2026-06-22
CVE-2026-6673 đŸ”ļ medium 6.4 0.2 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 authenticate Atlas... 2026-06-22
CVE-2026-8074 ℹī¸ low 3.8 0.2 Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to enforce bot-specific permission checks on the user act... 2026-06-22
CVE-2026-9162 đŸ”ļ medium 4.3 0.2 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 invalidate cached ... 2026-06-22
CVE-2026-8823 ℹī¸ low 3.8 0.2 Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to validate bot targets when demoting users to guests whi... 2026-06-22
CVE-2026-3433 đŸ”ļ medium 4.3 0.2 Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to restrict role_u... 2026-06-12
These CVEs affect the same products