Vulnerability

CVE-2026-7387

High· 8.8CVSS8.8

.rules3/5

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 Mattermost fails to require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints, which allows a user with group-link permissions to escalate themselves and group members to team or channel admin via crafted API requests.. Mattermost Advisory ID: MMSA-2026-00665

Threat signal

88/100

Severe

Severity

high

CVSS

8.8

EPSS

—

Active

CVSS

v3.1via NVDOpen in FIRST calculator →

8.8/ 10HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack VectorNetworkExploitable remotely over the internet — no local access needed.
Attack ComplexityLowNo special conditions — exploit works reliably.
Privileges RequiredLowStandard user privileges sufficient.
User InteractionNoneFully automated — no victim action needed.
ScopeUnchangedImpact contained to the vulnerable component.
Confidentiality ImpactHighTotal disclosure of sensitive data.
Integrity ImpactHighTotal compromise of integrity — full data modification possible.
Availability ImpactHighTotal loss of availability — full DoS possible.

EPSS

No EPSS data

FIRST.org publishes EPSS daily. Coverage isn't universal — pre-disclosure CVEs and reserved IDs don't carry an EPSS score until at least one exploitation signal lands. Score will appear within 24 hours of the next EPSS pull.

Vendor VEX

No VEX statements published for CVE-2026-7387. Vendors publish VEX (Vulnerability Exploitability eXchange) to assert per-product whether a CVE is actually exploitable in their distribution.

SSVCTrack

Total impact on non-trivial mission systems

exploitation: none
automatable: yes
impact: total
mission: support

Lifecycle

2026-06-12Published
2026-06-12Last modified1 source

References

https://mattermost.com/security-updates

No source-event history recorded yet. New revisions will appear here as ingestors re-fetch this CVE.