CVE-2026-6292 Overview
CVE-2026-6292 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the MP Customize Login Page plugin for WordPress in all versions up to and including 1.0. The flaw resides in the enter_mpclp_login_options() function, which contains broken nonce validation logic and lacks a capability check on the init hook. Attackers can trick a logged-in administrator into submitting a crafted request that modifies plugin settings, including login page background, logo URL, image dimensions, button colors, and login message. The vulnerability is tracked under CWE-352.
Critical Impact
Unauthenticated attackers can modify all plugin settings by tricking a logged-in administrator into clicking a malicious link, potentially altering the WordPress login page appearance and message.
Affected Products
- MP Customize Login Page plugin for WordPress, all versions through 1.0
- WordPress sites with the plugin installed and active
- Administrator accounts authenticated to vulnerable WordPress instances
Discovery Timeline
- 2026-06-24 - CVE-2026-6292 published to NVD
- 2026-06-25 - Last updated in NVD database
Technical Details for CVE-2026-6292
Vulnerability Analysis
The vulnerability stems from two compounding defects in the plugin's settings-update handler. First, the enter_mpclp_login_options() function implements an inverted nonce check written as if wp_verify_nonce(...) { return false; }. This logic returns early only when the nonce is valid, allowing execution to continue when the nonce is invalid or missing.
Second, the call to wp_verify_nonce() omits the required action parameter, further weakening the check. As a result, a CSRF-supplied empty or invalid nonce always returns false, satisfying the inverted condition and permitting the handler to process the request.
The settings-update handler is also registered on the init hook without any current_user_can() capability check. Any request reaching init while an administrator is authenticated will execute the settings update logic.
Root Cause
The root cause is a combination of inverted boolean logic in nonce verification, a missing action argument to wp_verify_nonce(), and the absence of a capability check on a privileged settings handler. The nonce code is effectively dead code that never blocks malicious requests.
Attack Vector
An unauthenticated attacker hosts a page containing a crafted form or auto-submitting JavaScript that targets the WordPress admin endpoint. When a logged-in administrator visits the attacker-controlled page, the browser submits the request with the administrator's session cookies. The broken nonce check passes, and the plugin writes attacker-controlled values to login page settings such as background image, logo URL, image dimensions, button colors, and the login message. See the Wordfence Vulnerability Report and the WordPress Plugin Source Code for technical details.
Detection Methods for CVE-2026-6292
Indicators of Compromise
- Unexpected changes to login page branding, background image, logo URL, or login message text on WordPress sites running the plugin.
- POST requests to the WordPress site root or admin endpoints from external Referer headers targeting MP Customize Login Page option names.
- Modifications to plugin options in wp_options rows associated with mpclp_ settings without a corresponding administrator action in audit logs.
Detection Strategies
- Monitor WordPress wp_options table changes related to MP Customize Login Page settings and correlate with admin user activity timelines.
- Inspect web server access logs for POST requests from cross-origin Referer values while an administrator session cookie is present.
- Deploy a Web Application Firewall (WAF) rule that flags state-changing requests to the plugin's option keys lacking a valid same-origin Referer and Origin header.
Monitoring Recommendations
- Enable WordPress audit logging to capture administrator option changes and review them daily.
- Alert on integrity changes to the login page rendered HTML through external uptime or content-monitoring tools.
- Track plugin inventory across managed WordPress sites and flag installations of MP Customize Login Page version 1.0 or earlier.
How to Mitigate CVE-2026-6292
Immediate Actions Required
- Deactivate and remove the MP Customize Login Page plugin from all WordPress sites until a patched version is published.
- Audit current plugin settings and revert any unauthorized changes to login page branding or messaging.
- Require administrators to log out of WordPress before browsing untrusted sites and enforce short session lifetimes.
Patch Information
At the time of publication, no fixed version has been listed in the NVD entry for CVE-2026-6292. All versions through 1.0 are affected. Review the Wordfence Vulnerability Report for updates on a vendor-supplied fix.
Workarounds
- Remove the plugin entirely if customization of the login page is not business-critical.
- Restrict access to /wp-admin and /wp-login.php by source IP using web server or WAF rules to reduce CSRF exposure.
- Deploy a WAF policy that blocks cross-origin POST requests targeting WordPress administrative endpoints when Origin or Referer headers do not match the site domain.
# Configuration example: remove the vulnerable plugin via WP-CLI
wp plugin deactivate mp-customize-login-page
wp plugin delete mp-customize-login-page
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
