High severity7.1NVD Advisory· Published Sep 14, 2026· Updated Sep 14, 2026
CVE-2026-8821
CVE-2026-8821
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
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
1- Range: <=11.9.0, <=11.8.4, <=11.7.7, <=10.11.22
Patches
Vulnerability mechanics
References
1News mentions
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