CVE-2026-76214

Analyzed Analyzed - Analysis Complete

phpMyFAQ WebAuthn Replay Attack Vulnerability

Publication date: 2026-08-19

Last updated on: 2026-09-01

Assigner: VulnCheck

Description

phpMyFAQ before 4.1.7 fails to persist the WebAuthn login challenge generated by prepareForLogin, because neither WebAuthn controller saves the mutated key objects back to the database. At login the anti-replay comparison is skipped by its own null guard, allowing an attacker who captures a successful WebAuthn assertion to replay it indefinitely and authenticate as the user without any interaction or hardware key.

CVSS Scores

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Meta Information

Published

2026-08-19

Last Modified

2026-09-01

Generated

2026-09-09

AI Q&A

2026-08-19

EPSS Evaluated

2026-09-07

NVD

CVE-2026-76214

EUVD

EUVD-2026-62455

Affected Vendors & Products

Vendor	Product	Version / Range
phpmyfaq	phpmyfaq	to 4.1.7 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-294	A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).

Attack-Flow Graph

Executive Summary

This vulnerability affects phpMyFAQ versions before 4.1.7. It involves a failure to save WebAuthn login challenges generated during authentication. Attackers can capture a valid WebAuthn assertion and replay it indefinitely to gain unauthorized access without needing a physical hardware key or user interaction.

Detection Guidance

To detect this vulnerability, check if your phpMyFAQ instance is running a vulnerable version (4.1.5 or earlier). Inspect the WebAuthn login flow for improper challenge persistence. Look for repeated successful authentications without new hardware key interactions.

Impact Analysis

An attacker could impersonate you on a vulnerable phpMyFAQ instance by replaying a captured WebAuthn assertion. This allows full unauthorized access to user accounts, potentially exposing sensitive data stored in phpMyFAQ without requiring additional authentication factors.

Compliance Impact

This vulnerability could lead to unauthorized data access, violating confidentiality requirements in GDPR and HIPAA. It undermines authentication security controls required by these regulations, potentially resulting in compliance violations and data breach notifications.

Mitigation Strategies

Upgrade phpMyFAQ to version 4.1.7 or later immediately. Ensure the WebAuthn login challenge is properly persisted after generation. Verify the anti-replay mechanism is functioning by testing authentication attempts.

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