CVE-2026-53592 FreeScout vulnerable to prototype pollution in getQueryParam
Attackers can pollute JavaScript prototypes via crafted URL query strings in FreeScout, potentially leading to code execution or security bypasses.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-53592?
CVE-2026-53592 is a medium-severity code injection vulnerability in freescout-help-desk freescout, published on 20 Jul 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. A Prototype Pollution condition in the `getQueryParam` function `/public/js/main.js` and was addressed in version 1.8.139 by blocking URL query keys matching the pattern `__proto__`. However, this mitigation is incomplete: it only filters top-level `__proto__` keys and fails to sanitize nested forms such as `b[__proto__][polluted]=PWNED`. As a result, an attacker-controlled URL query string can still write into `Object.prototype` on any page that loads `main.js`. Version 1.8.223 contains a updated fix.
Weakness: CWE-1321
Which versions are affected by CVE-2026-53592?
How do I fix CVE-2026-53592?
No fix has been published for CVE-2026-53592 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-53592 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53592 exists.
Sources
Also known as GHSA-w5fc-8pp3-f755.