CVE-2026-8821 - Playbooks run owner channel membership permission bypass
CVE ID :CVE-2026-8821
Published : Sept. 14, 2026, 10:42 a.m. | 24 minutes ago
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
Severity: 7.1 | HIGH
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Published : Sept. 14, 2026, 10:42 a.m. | 24 minutes ago
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
Severity: 7.1 | HIGH
Visit the link for more details, such as CVSS details, affected products, timeline, and more...