What is GHSA-8r89-8w26-cq32?

GHSA-8r89-8w26-cq32 is a security advisory published by GitHub Security Advisories with Medium severity. Mattermost versions 11.5.x \u003c= 11.5.1 fail to verify channel membership when processing AI...

Which CVE IDs does GHSA-8r89-8w26-cq32 cover?

GHSA-8r89-8w26-cq32 covers the following CVE IDs: CVE-2026-5163. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of GHSA-8r89-8w26-cq32?

GHSA-8r89-8w26-cq32 has a CVSS v3 base score of 6.5, published by GitHub Security Advisories.

GHSA-8r89-8w26-cq32MediumCVSS 6.5

Mattermost versions 11.5.x <= 11.5.1 fail to verify channel membership when processing AI...

Vendor

GitHub Security Advisories

Published

May 18, 2026

Last Modified

May 18, 2026

🔗 CVE IDs covered (1)

CVE-2026-5163 →

📋 Description

Mattermost versions 11.5.x <= 11.5.1 fail to verify channel membership when processing AI-assisted message rewrites which allows an authenticated attacker to read the content of threads in private channels and direct messages they do not have access to via a crafted request to the post rewrite endpoint.. Mattermost Advisory ID: MMSA-2026-00645

🔗 References (3)

https://nvd.nist.gov/vuln/detail/CVE-2026-5163
https://mattermost.com/security-updates
https://github.com/advisories/GHSA-8r89-8w26-cq32