CVE-2026-39666
Received Received - Intake
DOM-Based XSS in Hello Bar Popup Builder

Publication date: 2026-04-08

Last updated on: 2026-04-08

Assigner: Patchstack

Description
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in telepathy Hello Bar Popup Builder hellobar allows DOM-Based XSS.This issue affects Hello Bar Popup Builder: from n/a through <= 1.5.1.
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Meta Information
Published
2026-04-08
Last Modified
2026-04-08
Generated
2026-06-16
AI Q&A
2026-04-08
EPSS Evaluated
2026-06-15
NVD
CVE-2026-39666
EUVD
EUVD-2026-20340
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
hellobar popup_builder From 1.0.0 (inc) to 1.5.1 (inc)
Helpful Resources
Exploitability
CWE
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KEV
KEV Icon
CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
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Compliance Impact

The provided information does not specify any direct impact of this vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.

Executive Summary

CVE-2026-39666 is a Cross Site Scripting (XSS) vulnerability in the WordPress Hello Bar Popup Builder Plugin versions up to and including 1.5.1.

This vulnerability allows attackers to inject malicious scripts—such as redirects, advertisements, or other HTML payloads—into websites using the plugin. These scripts execute when visitors access the affected site.

The issue is classified under OWASP Top 10 A3: Injection and has a CVSS severity score of 6.5, indicating a moderate risk level.

Exploitation requires a user with at least Contributor or Developer privileges to perform an action like clicking a malicious link, visiting a crafted page, or submitting a form, meaning user interaction is necessary.

Impact Analysis

This vulnerability can impact you by allowing attackers to inject and execute malicious scripts on your website, which can lead to:

  • Redirecting visitors to malicious or unwanted websites.
  • Displaying unauthorized advertisements or unwanted content.
  • Potentially compromising user data or session information through script execution.

Although it is used in mass-exploit campaigns targeting many websites, it is considered a moderate risk and currently has no reported impactful threat.

Mitigation Strategies

The recommended immediate mitigation is to update the Hello Bar Popup Builder plugin once an official patch is released.

Until a patch is available, seek assistance from your hosting provider or web developers to implement temporary protections.

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