CVE-2026-3551 json
Custom New User Notification <= 1.2.0 - Authenticated (Administrator+) Stored Cross-Site Scripting via 'User Mail Subject' Setting
published 2026-04-16 6 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-23179
- cvss
- 4.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 30%
- public exploits
- 0
- none known
Summary
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.
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 6 mo ago
Exploit prediction
0.36% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 4.4 | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N |
Affected products
- rafasashi Custom New User Notification
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
- Technology feeds
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#L46
- plugins.trac.wordpress.org /browser/custom-new-user-notification/tags/1.2.0/admin/includes.php#L46
- plugins.trac.wordpress.org /browser/custom-new-user-notification/trunk/admin/includes.php#L52
- plugins.trac.wordpress.org /browser/custom-new-user-notification/tags/1.2.0/admin/includes.php#L52
- plugins.trac.wordpress.org /browser/custom-new-user-notification/trunk/admin/includes.php#L59
- plugins.trac.wordpress.org /browser/custom-new-user-notification/tags/1.2.0/admin/includes.php#L59
- plugins.trac.wordpress.org /browser/custom-new-user-notification/trunk/admin/includes.php#L84
- plugins.trac.wordpress.org /browser/custom-new-user-notification/tags/1.2.0/admin/includes.php#L84
- plugins.trac.wordpress.org /browser/custom-new-user-notification/trunk/admin/includes.php#L90
- plugins.trac.wordpress.org /browser/custom-new-user-notification/tags/1.2.0/admin/includes.php#L90
- plugins.trac.wordpress.org /browser/custom-new-user-notification/trunk/admin/includes.php#L97
- plugins.trac.wordpress.org /browser/custom-new-user-notification/tags/1.2.0/admin/includes.php#L97
- plugins.trac.wordpress.org /browser/custom-new-user-notification/trunk/admin/includes.php#L132
- plugins.trac.wordpress.org /browser/custom-new-user-notification/tags/1.2.0/admin/includes.php#L132
- plugins.trac.wordpress.org /browser/custom-new-user-notification/trunk/custom-new-user-notification.php#L63
- plugins.trac.wordpress.org /browser/custom-new-user-notification/tags/1.2.0/custom-new-user-notification.php#L63
Sources
- CVE List CVE-2026-3551
- NVD CVE-2026-3551
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.