Simple Custom Login Page <= 1.0.3 — Authenticated (Admin+) Stored Cross-Site Scripting

Am I affected?

• Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Simple Custom Login Page.
• No admin access? Run a passive check of your site. It reads public files only.

What to do

1. Update to version 1.0.4, or a newer patched version
2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
3. Watch Simple Custom Login Page to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to Nguyen Duong.

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.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

• Advisorywordfence.com

Related CVEs

Timeline

1. Jun 1, 2026

   CVE published

   Severity medium, CVSS 4.4

2. Nov 13, 2026

   Record last updated