CyberRota Analysis
This is a medium severity vulnerability with a CVSS score of 5.7. See the original NVD description below for full technical details.
CVE
CVE-2026-27656
Severity
MEDIUM
CVSS
5.7
EPSS
0.18%
Original NVD Description
Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to properly validate user identity in the OpenID {{IsSameUser()}} comparison logic, which allows an attacker to take over arbitrary user accounts via an overly permissive substring matching flaw in the user discovery flow.. Mattermost Advisory ID: MMSA-2026-00590
Related CVEs
Other vulnerabilities affecting the same vendor(s)