CVE-2026-12417: WordPress SignUp & SignIn Auth Bypass Flaw

CVE-2026-12417 Overview

CVE-2026-12417 is an authentication bypass vulnerability in the SignUp & SignIn plugin for WordPress, affecting all versions up to and including 1.0.0. The flaw resides in the pravel_change_password() AJAX handler, which is registered via wp_ajax_nopriv_pravel_change_password and exposed to unauthenticated requests. The handler performs no nonce verification and no capability check, relying only on a loose equality comparison between an attacker-supplied reset_activation_code and the target user's forgot_email user meta value. When a user has never initiated a password reset, the meta value is empty and trivially matches an omitted attacker code. The vulnerability is classified as [CWE-640: Weak Password Recovery Mechanism for Forgotten Password].

Critical Impact
Unauthenticated attackers can reset the password of any WordPress account, including administrators, resulting in full site takeover.

Affected Products

SignUp & SignIn plugin for WordPress, versions <= 1.0.0
WordPress sites with the wp_ajax_nopriv_pravel_change_password action exposed
Any administrator or user account on affected installations

Discovery Timeline

2026-06-24 - CVE-2026-12417 published to NVD
2026-06-25 - Last updated in NVD database

Technical Details for CVE-2026-12417

Vulnerability Analysis

The SignUp & SignIn plugin registers pravel_change_password() as both an authenticated and an unauthenticated AJAX action. The wp_ajax_nopriv_ prefix makes the handler reachable by any visitor without a session. Inside the handler, the plugin reads reset_user_id, new_password_custom, and reset_activation_code directly from the POST body. It then retrieves the forgot_email user meta for the target user and compares it against the attacker-supplied code using loose equality. No nonce, capability, or request origin is validated, leaving privileged actions reachable from anonymous network requests.

Root Cause

The root cause is the combination of an unauthenticated AJAX endpoint with a missing-value comparison in the password reset flow. When get_user_meta() returns an empty string for a user who has never used the forgot-password feature, that empty string evaluates equal to any falsy or omitted attacker input under PHP's loose == comparison. The handler then calls wp_set_password() on the targeted user identifier with the attacker-supplied value.

Attack Vector

An unauthenticated attacker sends a single POST request to admin-ajax.php containing action=pravel_change_password, reset_user_id set to the target user's numeric ID (administrators commonly have ID 1), and new_password_custom set to a chosen password. The reset_activation_code parameter can be empty or omitted. The server overwrites the target account's password, and the attacker authenticates through wp-login.php with the new credentials, gaining administrator-level access to the site.

For technical details of the vulnerable function, see the WordPress Plugin Function Code and the Wordfence Vulnerability Analysis.

Detection Methods for CVE-2026-12417

Indicators of Compromise

POST requests to /wp-admin/admin-ajax.php containing the parameter action=pravel_change_password from unauthenticated sources.
Unexplained password changes for administrator or editor accounts, particularly for user ID 1.
New administrator sessions originating from IP addresses with no prior login history.
Unexpected installation of plugins, themes, or files following a successful login event.

Detection Strategies

Inspect web server access logs for POST requests to admin-ajax.php where the body contains pravel_change_password.
Correlate wp_set_password or password-update events in WordPress audit logs with no preceding password-reset email request.
Alert on administrator authentication immediately following an admin-ajax.php POST from the same client IP.

Monitoring Recommendations

Forward WordPress and web server logs to a centralized analytics platform for correlation across requests and authentication events.
Enable a WordPress activity logging plugin to capture password resets, role changes, and plugin installations.
Monitor outbound requests from the WordPress host for callbacks or webshell traffic added by a compromised administrator.

How to Mitigate CVE-2026-12417

Immediate Actions Required

Deactivate and remove the SignUp & SignIn plugin until a patched version is released by the vendor.
Force a password reset for all WordPress accounts, prioritizing administrator and editor roles.
Review user lists for unauthorized accounts and remove any administrator that cannot be attributed to a known operator.
Rotate WordPress secret keys in wp-config.php to invalidate existing sessions.

Patch Information

No fixed version is listed in the NVD entry for CVE-2026-12417 at the time of publication. Administrators should monitor the Wordfence Vulnerability Analysis and the plugin's WordPress.org page for an updated release. Until a patched version is published, removal of the plugin is the only complete remediation.

Workarounds

Block POST requests to admin-ajax.php where the action parameter equals pravel_change_password at the web application firewall or reverse proxy.
Restrict access to /wp-admin/ and admin-ajax.php to known administrator IP ranges where operationally feasible.
Enforce multi-factor authentication on all WordPress accounts to limit the impact of a successful password reset.

bash

# Example nginx rule to block exploitation attempts
if ($request_method = POST) {
    if ($request_uri ~* "/wp-admin/admin-ajax\.php") {
        if ($request_body ~* "action=pravel_change_password") {
            return 403;
        }
    }
}