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Vulnerabilities

Vulnerability · CVE-2026-3551

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.

Published Apr 16, 2026 · catalog updated Jun 17, 2026 · The Custom New User

Check if you run it

No confirmed exploitation is on record for CVE-2026-3551. EPSS is 0.41%. Act only if a listed version of The Custom New User is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (The Custom New User).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium4.4
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.41%
Remediation
Version ranges on file
Affected products
stated named in the record

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • stated named in the record<= 1.2.0

How to fix CVE-2026-3551

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-3551. EPSS is 0.41%. Act only if a listed version of The Custom New User is installed.

Which versions are affected?

Compare what you have installed with named in the record <= 1.2.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-79: Cross-site Scripting (XSS). EPSS 0.41%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

WordPress security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 16, 2026 · NIST NVD

    Detected

    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 Emai

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 Emai

Sources

  • CVE.orgVulnerability recordCVE-2026-3551

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-3551

    30-day exploitation probability 0.4%

    first.org
  • NIST NVDVulnerability recordCVE-2026-3551

    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

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.