CVE-2026-103514: WP 2FA WordPress Auth Bypass Vulnerability

CVE-2026-103514 Overview

CVE-2026-103514 is an authentication weakness in the WP 2FA WordPress plugin before version 4.1.0. The plugin fails to invalidate time-based one-time passcodes (TOTP) after they are consumed. An attacker who already knows a valid password and captures a TOTP within its validity window can replay the code to bypass two-factor authentication (2FA), including on administrator accounts. The flaw is classified as Improper Authentication [CWE-287].

Critical Impact
Attackers with stolen credentials and a captured TOTP can replay the code to log in as any user, including administrators, defeating the plugin's second authentication factor.

Affected Products

WP 2FA WordPress plugin versions prior to 4.1.0
WordPress sites relying on WP 2FA for TOTP-based authentication
Administrator and standard user accounts protected by WP 2FA

Discovery Timeline

2026-10-03 - CVE-2026-103514 published to NVD
2026-10-06 - Last updated in NVD database

Technical Details for CVE-2026-103514

Vulnerability Analysis

TOTP codes are designed as one-time secrets. Each generated code must be accepted exactly once within its short validity window, typically 30 seconds. WP 2FA before 4.1.0 verifies the TOTP against the shared secret but does not record used codes. The same code remains valid for repeated submissions until its time step expires.

This gap breaks the single-use guarantee of RFC 6238. An attacker who observes a legitimate code, through phishing, network interception, shoulder surfing, or malware on the victim's device, can replay it against the login endpoint. Because 2FA bypass extends to administrator accounts, successful exploitation yields full WordPress site compromise, including plugin installation, content modification, and database access.

Root Cause

The root cause is missing replay protection in the TOTP verification routine. The plugin does not maintain a server-side ledger of consumed codes or counters associated with the active time step. Without this state tracking, the verification logic treats every valid-looking submission as fresh, violating the one-time property required by TOTP.

Attack Vector

Exploitation requires the attacker to possess the victim's password and observe a valid TOTP code before it expires. The attack is network-based, requires low privileges, and no user interaction at the moment of replay. Attack complexity is rated high because the attacker must obtain both factors within the TOTP validity window. Once both are obtained, the attacker submits the captured credentials and the replayed TOTP to the WordPress login endpoint to authenticate.

The vulnerability is described in prose only. See the WPScan Vulnerability Report for additional technical details.

Detection Methods for CVE-2026-103514

Indicators of Compromise

Multiple successful logins for the same account from different IP addresses within a single TOTP time step (30 seconds).
Repeated authentication attempts submitting identical TOTP codes against wp-login.php for the same user.
Administrator logins immediately followed by plugin installation, user creation, or theme file edits from unfamiliar source IPs.

Detection Strategies

Correlate WordPress authentication logs with web server access logs to flag reuse of the same 6-digit code across sessions.
Alert on geographically improbable successful logins occurring within seconds of each other for the same user.
Monitor for new administrator accounts, modified user roles, or unexpected plugin uploads following successful 2FA authentication.

Monitoring Recommendations

Enable verbose authentication logging in WP 2FA and forward events to a centralized logging platform for correlation.
Track failed and successful logins per account and alert on anomalous patterns such as back-to-back successful authentications.
Review the WP 2FA plugin version across all managed WordPress sites and flag any instance running a version earlier than 4.1.0.

How to Mitigate CVE-2026-103514

Immediate Actions Required

Upgrade WP 2FA to version 4.1.0 or later on every WordPress site in the environment.
Force a password reset for all administrator accounts and any user whose credentials may have been exposed.
Audit recent administrator activity for unauthorized plugin installations, user changes, or content modifications.

Patch Information

The vendor addressed the issue in WP 2FA version 4.1.0 by invalidating TOTP codes after use. Refer to the WPScan Vulnerability Report for release details.

Workarounds

Enforce strong, unique passwords and account lockout policies to raise the cost of acquiring the first factor.
Restrict access to wp-login.php and wp-admin by IP allow-list or web application firewall rules where feasible.
Consider switching administrator accounts to hardware security keys (WebAuthn/FIDO2) if supported, which are not replayable.

bash

# Example: restrict wp-admin access via nginx allow-list
location ~ ^/(wp-admin|wp-login\.php) {
    allow 203.0.113.0/24;   # trusted admin network
    deny all;
    include fastcgi_params;
    fastcgi_pass unix:/var/run/php-fpm.sock;
}