CVE-2026-15273 PUBLISHED

The Automatic.css plugin for WordPress is vulnerable to Stored Cross-Site Scripting via REQUEST_URI in all version 4.0.0 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts that will execute whenever an administrator accesses the Activity Log settings page.

• Nguyen Ngoc Duc (duc193) finder

• https://www.wordfence.com/threat-intel/vulnerabilities/id/07d697c5-1c15-4d3a-8637-cc4fd408f209?source=cve
• https://plugins.trac.wordpress.org/browser/automaticcss-plugin/trunk/classes/UI/Settings_Page/Activity_Log.php#L90
• https://plugins.trac.wordpress.org/browser/automaticcss-plugin/trunk/classes/Helpers/Logger.php#L187
• https://plugins.trac.wordpress.org/browser/automaticcss-plugin/trunk/classes/Plugin.php#L175
• https://plugins.trac.wordpress.org/browser/automaticcss-plugin/trunk/classes/Lib/WideEvents/Formatter/JsonFormatter.php#L25
• https://automaticcss.com/changelogs/

• CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE