phpMyFAQ 3.2.0 before 4.0.0 and 4.0.2 before 4.2.0-beta contains an authentication bypass in its Microsoft Entra ID login flow, which links users by the mutable preferred_username claim and whose AuthEntraId::create() ignores the duplicate-login exception while continuing with the existing local account. Attackers controlling an Entra identity in the configured tenant with a matching preferred_username can take over that local account, including super-admin accounts.
https://github.com/thorsten/phpMyFAQ/security/advisories/GHSA-6hhv-gc4g-f4r7
Published: 2026-10-17
Updated: 2026-10-17
Base Score: 6.6
Vector: CVSS2#AV:N/AC:H/Au:S/C:C/I:C/A:N
Severity: Medium
Base Score: 6.8
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
Severity: Medium
Base Score: 7.6
Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Severity: High