What is CVE-2026-27769?

CVE-2026-27769 is a low-severity vulnerability in Mattermost, classified under Missing Authorization. CVSS score: 2.7/10. Published 2026-04-15.

How severe is CVE-2026-27769?

Low severity. CVSS v3 base score is 2.7 out of 10.

Auth bypass in Mattermost

CVE-2026-27769

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…

Vulnerability class: Broken Access Control

EPSS: 0.000 (11.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 2.7 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:N.

Affected products

Mattermost — versions 10.11.0, 11.5.0, 10.11.13

Weakness classification (CWE)

CWE-862 — Missing Authorization

References

MMSA-2026-00603 (vendor-advisory)

Frequently asked questions

What is CVE-2026-27769?: CVE-2026-27769 is a low-severity vulnerability in Mattermost, classified under Missing Authorization. CVSS score: 2.7/10. Published 2026-04-15.
How severe is CVE-2026-27769?: Low severity. CVSS v3 base score is 2.7 out of 10.