CVE-2026-3551
Custom New User Notification <= 1.2.0 - Authenticated (Administrator+) Stored Cross-Site Scripting via 'User Mail Subject' Setting
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
4.4
Custom New User Notification <= 1.2.0 - Authenticated (Administrator+) Stored Cross-Site Scripting via 'User Mail Subject' Setting
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.
- Record
CVE-2026-3551- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2026-23179
4.4
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.
- Record
EUVD-2026-23179- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-4xx2-h7jh-g7ph
4.4
The Custom New User Notification plugin for WordPress is vulnerable to Stored Cross-Site...
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.
- Record
GHSA-4xx2-h7jh-g7ph- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
4.4
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.
- Record
CVE-2026-3551- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-3551 is a medium vulnerability (CVSS 4.4) in Rafasashi Custom New User Notification, published April 16, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.36%, the 30th percentile. No source names a fixed version.
References
wordfence.com/threat-intel/vulnerabilities/id/7a14d35d-144c-4ddd-b288-5e0e006fb165?source=cve
plugins.trac.wordpress.org/browser/custom-new-user-notification/trunk/admin/includes.php
plugins.trac.wordpress.org/browser/custom-new-user-notification/tags/1.2.0/admin/includes.php
plugins.trac.wordpress.org/browser/custom-new-user-notification/trunk/custom-new-user-notification.php
plugins.trac.wordpress.org/browser/custom-new-user-notification/tags/1.2.0/custom-new-user-notification.php
nvd.nist.gov/vuln/detail/CVE-2026-3551
github.com/advisories/GHSA-4xx2-h7jh-g7ph