What is GHSA-wrc8-ccxq-937h?

GHSA-wrc8-ccxq-937h is a security advisory published by GitHub Security Advisories with High severity. Mattermost versions 11.9.x \u003c= 11.9.0, 11.8.x \u003c= 11.8.4, 11.7.x \u003c= 11.7.7, 10.11.x \u003c= 10.11.22...

Which CVE IDs does GHSA-wrc8-ccxq-937h cover?

GHSA-wrc8-ccxq-937h covers the following CVE IDs: CVE-2026-8821. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of GHSA-wrc8-ccxq-937h?

GHSA-wrc8-ccxq-937h has a CVSS v3 base score of 7.1, published by GitHub Security Advisories.

GHSA-wrc8-ccxq-937hHighCVSS 7.1

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...

Vendor

GitHub Security Advisories

Published

September 14, 2026

Last Modified

September 14, 2026

🔗 CVE IDs covered (1)

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

🔗 References (3)

https://nvd.nist.gov/vuln/detail/CVE-2026-8821
https://mattermost.com/security-updates
https://github.com/advisories/GHSA-wrc8-ccxq-937h