# CVE-2026-53592: FreeScout Prototype Pollution in getQueryParam function

Source: https://junglewise.ai/threats/cve-2026-53592-freescout-prototype-pollution-in-getqueryparam-function  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-20. Updated: 2026-07-20  
License: CC BY 4.0 with a link back

CVE-2026-53592 · Severity: medium · CVSS 4.6 · Published 2026-07-20

FreeScout is an open-source help desk and shared inbox platform. A security flaw in its web interface allows an attacker to manipulate the underlying JavaScript environment by sending a specially crafted link to a logged-in user. This could potentially lead to unauthorized changes in how the application behaves, such as redirecting users to malicious sites or stealing sensitive information if combined with other vulnerabilities.

## Quick answers

**Is CVE-2026-53592 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-53592 being exploited in the wild.

**How severe is CVE-2026-53592?** Medium severity, with a CVSS score of 4.6, published 20 July 2026.

**Which products and versions are affected?** freescout-help-desk FreeScout < 1.8.223.

**Is there a fix for CVE-2026-53592?** 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-2026-53592 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-53592?** 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

A Prototype Pollution vulnerability exists in the `getQueryParam` function within `/public/js/main.js` of FreeScout. While a previous fix (v1.8.139) attempted to block the `__proto__` key, it only checked if the top-level query parameter started with that string. An attacker can bypass this by using nested bracket notation, such as `b[__proto__][polluted]=value`, which the regex fails to catch. This allows an authenticated attacker to inject properties into the global `Object.prototype` via a crafted URL. If the application later uses these polluted properties in a sensitive context, it could lead to DOM-based XSS or other client-side attacks. The issue is fully resolved in version 1.8.223.

## Affected products

- freescout-help-desk FreeScout < 1.8.223

## Timeline

- 2026-06-10: advisory: GitHub Security Advisory published
- 2026-07-20: disclosed: CVE published to NVD

## References

- [https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-w5fc-8pp3-f755](https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-w5fc-8pp3-f755)