# CVE-2026-100186: User Profile Builder stored cross-site scripting in first name field

Source: https://junglewise.ai/threats/cve-2026-100186-the-user-profile-builder-beautiful-user-registration-forms-user  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-16. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-100186 · Severity: high · CVSS 7.2 · Published 2026-10-16

User Profile Builder is a WordPress plugin that lets website administrators create custom user registration and profile management forms. An unauthenticated attacker can inject malicious scripts into a user's first name field that will execute in the browsers of other users viewing that profile, potentially leading to credential theft or malware distribution. This vulnerability only affects sites with the Email Confirmation feature enabled.

Technologies: [Cozmoslabs User Profile Builder](https://junglewise.ai/threats/technologies/user-profile-builder). Vendors: [Cozmoslabs](https://junglewise.ai/threats/vendors/cozmoslabs).

## Quick answers

**Is CVE-2026-100186 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-100186 being exploited in the wild.

**How severe is CVE-2026-100186?** High severity, with a CVSS score of 7.2, published 16 October 2026.

**Which products and versions are affected?** Cozmoslabs User Profile Builder up to and including 4.0.3.

**Is there a fix for CVE-2026-100186?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-100186 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-100186?** Check whether you run Cozmoslabs User Profile Builder at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The plugin fails to properly sanitize and escape user input in the first name field when the Email Confirmation feature is enabled, allowing stored XSS injection. An unauthenticated attacker can craft malicious JavaScript in the first name field during registration, which persists in the database and executes in victims' browsers when they access pages displaying the injected profile data. The vulnerability exists in the email confirmation feature's handling of the first name field.

## Affected products

- Cozmoslabs User Profile Builder up to and including 4.0.3

## Timeline

- 2026-10-16: disclosed

## References

- [https://plugins.trac.wordpress.org/browser/profile-builder/tags/4.0.3/features/email-confirmation/class-email-confirmation.php](https://plugins.trac.wordpress.org/browser/profile-builder/tags/4.0.3/features/email-confirmation/class-email-confirmation.php)
- [https://plugins.trac.wordpress.org/browser/profile-builder/tags/4.0.3/features/email-confirmation/class-email-confirmation.php](https://plugins.trac.wordpress.org/browser/profile-builder/tags/4.0.3/features/email-confirmation/class-email-confirmation.php)

## Related threats

- [User Profile Builder reflected XSS in admin page](https://junglewise.ai/threats/cve-2026-111948-the-user-profile-builder-wordpress-plugin-before-4-0-1-does-not)
- [User Profile Builder privilege escalation via role parameter](https://junglewise.ai/threats/cve-2026-109447-the-user-profile-builder-beautiful-user-registration-forms-user)
- [User Profile Builder display_name stored XSS](https://junglewise.ai/threats/cve-2026-107748-the-user-profile-builder-beautiful-user-registration-forms-user)
- [User Profile Builder authentication bypass in file upload](https://junglewise.ai/threats/cve-2026-76548-user-profile-builder-authentication-bypass-in-file-upload)
- [User Profile Builder stored XSS in format date shortcode](https://junglewise.ai/threats/cve-2026-76546-user-profile-builder-stored-xss-in-format-date-shortcode)