Authentication Bypass by Capture-replay in phpMyFAQ - #VU140896
Published: August 4, 2026
Vulnerability identifier: #VU140896
CSH Severity: Medium
CVSS v4: 9.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-294
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass WebAuthn authentication by replaying a captured assertion.
The vulnerability exists due to missing critical step in authentication in the WebAuthn login flow when processing login assertions. A remote attacker can replay a captured login request body to bypass WebAuthn authentication by replaying a captured assertion.
The per-login challenge generated by prepareForLogin is not persisted, so the stored challenge is missing and the anti-replay check is skipped by a null guard. No user interaction or hardware key use is required once a valid assertion has been captured.
Affected software
phpMyFAQ
Remediation
Install security update from vendor's website.
phpMyFAQ - update to 4.1.7