WordPress security changelog
MEDIUM CVE-2026-3551 Deferred

Custom New User Notification: Cross-site scripting

Custom New User Notification is affected by cross-site scripting. Exploitation requires at least administrator-level access. Injected script can execute in the affected site's origin when the vulnerable output is viewed. The published affected range is <= 1.2.0.

CVE / CNA score 4.4 CVSS 3.1 · security@wordfence.com
NVD score Pending NVD has not published its own CVSS assessment.
Component
Custom New User Notification
Plugin slug
custom-new-user-notification
Affected
<= 1.2.0
Safe version
> 1.2.0
Published
Apr 16, 2026
Weakness
CWE-79 — Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

This CVE was published Apr 16, 2026 and is one of 1 known issue for this plugin.

What to do

Update, patch or deactivate.

Update Custom New User Notification to a release after 1.2.0, or disable and remove it until a fixed version is available.

A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.

Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.

Source record

Technical description

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.

CVE / CNA vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N

References

Primary and upstream sources