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CVE-2026-6739

7.2 highEPSS 0.3%

High (7.2) in mattermost mattermost server. EPSS 0.3% chance of exploitation in the next 30 days. Fixed in github.com/mattermost/mattermost-server 10.11.17, 10.11.17+incompatible, 11.5.5.

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 fail to require system-level permission when patching protected default system roles, which allows authenticated users with delegated user-management permissions to escalate privileges by altering built-in role permissions via the role patch API.. Mattermost Advisory ID: MMSA-2026-00656

Severity

CVSS 3.1

7.2 high
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
EPSS
0.3% chance of exploitation in the next 30 days; higher than 17% of CVEs (scores of 2026-10-31)
CWE
CWE-863
Published
Modified
Record from
the NVD, synced

Affected

Packages (OSV)

AdvisoryEcosystemPackageAffectedFixed in
GHSA-m2w9-h2mm-79qrGogithub.com/mattermost/mattermost-server>=11.6.0 <11.6.111.6.1
GHSA-m2w9-h2mm-79qrGogithub.com/mattermost/mattermost-server>=11.5.0 <11.5.511.5.5
GHSA-m2w9-h2mm-79qrGogithub.com/mattermost/mattermost-server>=10.11.0 <10.11.1710.11.17
GHSA-m2w9-h2mm-79qrGogithub.com/mattermost/mattermost/server/v8>=8.0.0-20250731163400-5b955468ea1e <8.0.0-20260501142004-99b73d4c4acf8.0.0-20260501142004-99b73d4c4acf
GO-2026-6285Gogithub.com/mattermost/mattermost-server>=10.11.0+incompatible <10.11.17+incompatible
>=11.5.0+incompatible <11.5.5+incompatible
>=11.6.0+incompatible <11.6.1+incompatible		10.11.17+incompatible, 11.5.5+incompatible, 11.6.1+incompatible
GO-2026-6285Gogithub.com/mattermost/mattermost-server/v5all versionsno fix published
GO-2026-6285Gogithub.com/mattermost/mattermost-server/v6all versionsno fix published
GO-2026-6285Gogithub.com/mattermost/mattermost/server/v8>=8.0.0-20250731163400-5b955468ea1e <8.0.0-20260501142004-99b73d4c4acf8.0.0-20260501142004-99b73d4c4acf

References

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