What the vulnerability does
01Description
The Custom New User Notification plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's admin settings in all versions up to, and including, 1.2.0. This is due to insufficient input sanitization and output escaping on multiple settings fields including 'User Mail Subject', 'User From Name', 'User From Email', 'Admin Mail Subject', 'Admin From Name', and 'Admin From Email'. The settings are registered via register_setting() without sanitize callbacks, and the values retrieved via get_option() are echoed directly into HTML input value attributes without esc_attr(). This makes it possible for authenticated attackers, with Administrator-level access and above, to inject arbitrary web scripts in the plugin settings page that will execute whenever a user accesses that page. This could be used in multi-site installations where administrators of subsites could target super administrators.
Explanation of Vulnerability in Simple Terms
02Summary
Custom New User Notification versions 1.2.0 and earlier contain a cross-site scripting (XSS) vulnerability. An attacker with high privileges can inject malicious scripts that execute in other users' browsers when the scope is changed. The vulnerability requires high attack complexity and does not require user interaction. Low confidentiality and integrity impact is possible.
What an attacker can do
03Attacker Capabilities
Inject malicious scripts that execute in other users' browsers to steal data or perform actions on their behalf.
Potential impact on your site
04Site Impact
Users' sessions and data could be compromised if an attacker with admin/editor access injects malicious scripts.
Conditions required to exploit
05Prerequisites
Attacker must have high-level privileges (e.g., admin or editor role) and network access to the site.
Key dates
06Disclosure timeline
April 16, 2026
CVE published
April 16, 2026
Record updated
