VULNERABILITY INTELLIGENCE

CVE-2026-8821

CVSS score7.1 HIGH
EPSS probability0.29%
CISA KEVNot currently listed
Published2026-09-14
Last modified2026-10-07
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

Description

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to validate channel member-management permission during playbook run creation, allowing an authenticated channel member to add an arbitrary user to a restricted channel via the run owner field.. Mattermost Advisory ID: MMSA-2026-00677

Weakness classification

  • responsibledisclosure@mattermost.com: CWE-862

Primary references