What is GHSA-mxxh-fmjq-j6x4?

GHSA-mxxh-fmjq-j6x4 is a security advisory published by GitHub Security Advisories with Low severity. Mattermost doesn't validate whether users were correctly owned by the correct Connected Workspace

Which CVE IDs does GHSA-mxxh-fmjq-j6x4 cover?

GHSA-mxxh-fmjq-j6x4 covers the following CVE IDs: CVE-2026-27769. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of GHSA-mxxh-fmjq-j6x4?

GHSA-mxxh-fmjq-j6x4 has a CVSS v3 base score of 2.7, published by GitHub Security Advisories.

Which products are affected by GHSA-mxxh-fmjq-j6x4?

GHSA-mxxh-fmjq-j6x4 affects 1 product, including: go/github.com/mattermost/mattermost-server:\u003e= 8.0.0-20250721062209-4952acea88ce, \u003c 8.0.0-20260316060126-bc1a2b34b1f9.

GHSA-mxxh-fmjq-j6x4LowCVSS 2.7

Mattermost doesn't validate whether users were correctly owned by the correct Connected Workspace

Vendor

GitHub Security Advisories

Published

April 17, 2026

Last Modified

April 28, 2026

🔗 CVE IDs covered (1)

CVE-2026-27769 →

📋 Description

Mattermost versions 10.11.x <= 10.11.12 fail to validate whether users were correctly owned by the correct Connected Workspace which allows a malicious remote server connected using the Conntexted Workspaces feature to change the displayed status of local users via the Connected Workspaces API. Mattermost Advisory ID: MMSA-2026-00603.

🎯 Affected products1

go/github.com/mattermost/mattermost-server:>= 8.0.0-20250721062209-4952acea88ce, < 8.0.0-20260316060126-bc1a2b34b1f9

🔗 References (3)

https://nvd.nist.gov/vuln/detail/CVE-2026-27769
https://mattermost.com/security-updates
https://github.com/advisories/GHSA-mxxh-fmjq-j6x4