VULNERABILITY INTELLIGENCE

CVE-2026-9859

CVSS score6.5 MEDIUM
EPSS probability0.34%
CISA KEVNot currently listed
Published2026-08-17
Last modified2026-08-19
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Description

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fail to enforce PermissionManageBoardRoles on the channelId field of the batch endpoint, which allows an authenticated board editor to relink any board they can edit to an arbitrary channel via a crafted PATCH request. Mattermost Advisory ID: MMSA-2026-00686

Weakness classification

  • responsibledisclosure@mattermost.com: CWE-863

Primary references