CVE-2026-85590

Summary

phpMyFAQ before 4.1.8 contains an authentication bypass vulnerability in its two-factor authentication (TOTP) disable functionality. The removeTwofactorConfig() handler (reachable via POST /api/user/remove-twofactor) verifies only that the user is logged in and that a valid CSRF token is supplied, then disables TOTP without requiring password re-entry or a current TOTP code. The same downgrade is also reachable inline via PUT /api/user/data/update, which accepts a plain twofactor_enabled form field under the same session+CSRF-only guard. An attacker who has hijacked a user's session can silently strip two-factor protection from any account, including administrator accounts, after which password-only authentication succeeds.

Affected Software

Weaknesses

• CWE-308: Use of Single-factor Authentication

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: poc
  • Automatable: no
  • Technical Impact: partial

Additional References

• https://github.com/thorsten/phpMyFAQ/security/advisories/GHSA-h96g-59xp-7r5m

References

• https://github.com/thorsten/phpMyFAQ/security/advisories/GHSA-h96g-59xp-7r5m
• https://www.vulncheck.com/advisories/phpmyfaq-before-4.1.8-authentication-bypass-via-two-factor-disable

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