Prototype Pollution in Freescout-Help-Desk Freescout
CVE-2026-53592
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.
Vulnerability class: Prototype Pollution
EPSS: 0.002 (9.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 4.6 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L.
Affected products
- Freescout-help-desk Freescout — versions < 1.8.223
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
Frequently asked questions
- What is CVE-2026-53592?
- CVE-2026-53592 is a medium-severity vulnerability in Freescout-Help-Desk Freescout, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 4.6/10. Published 2026-07-20.
- How severe is CVE-2026-53592?
- Medium severity. CVSS v3 base score is 4.6 out of 10.