Stop Using phpMyFAQ Versions Below 4.1.9 Due to Critical Login Bypass

phpMyFAQ allows attackers to take over user accounts by registering fake security keys without verifying who they are. This critical flaw affects software versions released before 4.1.9. According to National Vulnerability Database records, the vulnerability enables unauthenticated account takeover. System administrators using these older versions face immediate exposure. The issue stems from how the application handles WebAuthn registration requests. Attackers do not need to guess passwords or steal tokens. They can simply create a new credential for any existing user. This allows them to log in as that user immediately. The National Vulnerability Database assigns this flaw CVE-2026-111911.

In plain English

WebAuthn is a standard for passwordless login using security keys or biometrics. The vulnerability in phpMyFAQ breaks the trust model of this system. Normally, a server verifies a user's identity before attaching a new key to their account. In this case, the registration endpoints skip that verification step entirely. They also skip challenge validation. An attacker can send a request to add a new passkey to any username they choose. They use a forged attestation type called fmt=none to do this. Once the key is registered, the attacker can use it to log in.

The background

The flaw exists in phpMyFAQ versions 4.0.0 through the release before 4.1.9. The National Vulnerability Database classifies the weakness as CWE-287, which denotes improper authentication. This category covers failures in verifying the identity of a user or system. The specific issue allows credential attachment without prior authentication. Attackers can stage a victim's username first. Then they submit the forged attestation to register the passkey. This process bypasses standard password requirements. It also bypasses Time-based One-Time Passwords or other multi-factor methods. The result is full account access for the attacker.

What changes now

Organizations running phpMyFAQ must check their current version immediately. If the version is earlier than 4.1.9, the system is vulnerable. The National Vulnerability Database lists the affected range clearly. No other versions are mentioned as secure in the provided records. Administrators should prioritize updating their installations. Until an update is applied, the application remains exposed to unauthenticated takeover. Attackers can exploit this to gain control of user accounts. The risk is immediate and does not require complex tools.

Key terms explained

Teams usually verify user identity before linking new security credentials to an account. In this event, check whether your system validates requests before accepting changes. Look for endpoints that allow modifications without proof of ownership. Ensure that registration processes require a valid session or token. Review how your application handles passkey additions. Confirm that it rejects requests from unverified sources. Monitor logs for unusual registration activity from unknown locations. Verify that challenge-response mechanisms are active and enforced. Do not assume that password protection is sufficient if keys can be added freely.

Background: Account takeover

Detect account takeover by correlating login anomalies with behavioral shifts. Look for impossible travel, new device fingerprints, and sudden data exports. Combine identity logs with endpoint telemetry to spot compromised credentials before lateral movement occurs.

Read the full guide: Detect Account Takeover: Signals in Logs, Behavior, and Blind Spots

What to do and how to stay safe: phpMyFAQ

• Identify all instances of phpMyFAQ running versions prior to 4.1.9 on your network.
• Update affected installations to version 4.1.9 or later once the vendor provides an update.
• Monitor authentication logs for unauthorized passkey registrations or login attempts from unfamiliar devices.
• Enforce strict network access controls to limit exposure of the phpMyFAQ interface to trusted users only.

Step-by-step guide: Risk-Based Vulnerability Management: Benefits, Limits, and Reality

General security guidance from the Vector Update newsroom. It is not confirmed advice from the organisations named in this story.

Frequently asked questions

Which phpMyFAQ versions are affected by CVE-2026-111911?

phpMyFAQ versions 4.0.0 through any version before 4.1.9 are affected by this vulnerability.

What can attackers do with this flaw?

Attackers can register forged passkeys to bypass passwords and TOTP for account takeover.

Is this vulnerability considered critical?

Yes, the National Vulnerability Database rates the vulnerability as CVSS 9.3, which is critical.