Is CVE-2026-77115 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-77115 being exploited in the wild.

How severe is CVE-2026-77115?

High severity, with a CVSS score of 7.1, published 23 August 2026.

Which products and versions are affected?

Brave Popup Builder up to 0.8.5.

Is there a fix for CVE-2026-77115?

A patch was published on 2026-08-23: Fixed in version 0.8.6 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-77115 attacked?

It is attacked over the network, in a web application.

Am I affected by CVE-2026-77115?

Check whether anything you run is named in the advisory. 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.

CVE-2026-77115: Brave Popup Builder reflected XSS via UTM parameters

CVE-2026-77115 · Severity: high · CVSS 7.1 · Published 2026-08-23

Brave Popup Builder is a WordPress plugin used to create and display popup campaigns on websites. The plugin fails to properly escape user-supplied UTM tracking parameters before displaying them in popup form fields, allowing attackers to inject malicious code that executes in visitors' browsers without requiring any authentication or action beyond opening a crafted link. This could lead to session hijacking, credential theft, or malware distribution.

Quick answers

Is CVE-2026-77115 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-77115 being exploited in the wild.
How severe is CVE-2026-77115?: High severity, with a CVSS score of 7.1, published 23 August 2026.
Which products and versions are affected?: Brave Popup Builder up to 0.8.5.
Is there a fix for CVE-2026-77115?: A patch was published on 2026-08-23: Fixed in version 0.8.6 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-77115 attacked?: It is attacked over the network, in a web application.
Am I affected by CVE-2026-77115?: Check whether anything you run is named in the advisory. 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 vulnerability is a reflected cross-site scripting (XSS) flaw (CWE-79) affecting Brave Popup Builder versions up to 0.8.5. When a popup form is configured with fields that use "UTM Parameter" as the default value source, the plugin directly reflects the corresponding $_GET parameter into the HTML output without applying any escaping functions (esc_attr, esc_html, esc_textarea). The vulnerable code is located in lib/frontend/Form.php in the renderInput() (line 408), renderHidden() (lines 442-456), and renderTextarea() (lines 475-484) functions. An unauthenticated attacker can craft a malicious URL with injected HTML/JavaScript in UTM parameters (e.g., utm_source, utm_medium, utm_campaign) and send it to victims; when the page containing the popup loads, the payload executes in the victim's browser context regardless of session state. The vulnerability was fixed in version 0.8.6 by properly entity-encoding reflected values.

Affected products

Brave Popup Builder up to 0.8.5

Timeline

2026-08-21: disclosed
2026-08-23: patched: Fixed in version 0.8.6

References

https://wpscan.com/vulnerability/d4a760c0-8e71-4261-a08b-9b6a296c631a/

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