What the vulnerability does
01Description
The Simple Custom Login Page plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the color settings fields (Page Background, Form Background, Text Color, Link Color) in versions up to and including 1.0.3. This is due to insufficient input sanitization of the color option values (they were registered with register_setting() and stored via the Settings API/update_option() with no sanitize_callback) combined with the values being output into a <style> block on wp-login.php using esc_attr(), which is incorrect for a CSS context (it does not escape ;, {, }, / or *). This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary CSS rules into the login page that are rendered for all unauthenticated visitors, enabling UI-redress and credential-phishing attacks.
Explanation of Vulnerability in Simple Terms
02Summary
Simple Custom Login Page versions 1.0.3 and earlier contain a cross-site scripting (XSS) vulnerability in the login form. An authenticated administrator with high privileges can inject malicious scripts that execute in other users' browsers when they visit the login page. The vulnerability requires specific attack conditions and does not allow data theft or site disruption, but can be used to deface the login interface or redirect users.
What an attacker can do
03Attacker Capabilities
Inject and execute malicious JavaScript in the login page viewed by other users.
Potential impact on your site
04Site Impact
An admin account compromise could allow defacement of your login page or phishing attacks against your users.
Conditions required to exploit
05Prerequisites
Attacker must have high-level administrative privileges on the site; no user interaction required.
Key dates
06Disclosure timeline
June 2, 2026
CVE published
June 2, 2026
Record updated
