phpMyFAQ vulnerability

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.

Published 17 Oct 2026Updated 17 Oct 20262 sources
CVSS 7.6

What happened

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.

Affected versions

phpMyFAQ: 3.2.0 through before 4.0.0 (semver); 4.0.2 through before 4.2.0-beta (semver) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

  • Apply vendor-provided updates or mitigations.
  • Review affected product exposure and access logs.

Public PoC references

No public PoC reference has passed the current publication threshold.