What’s Vulnerable › Vulnerabilities

CVE-2026-53592: FreeScout vulnerable to prototype pollution in getQueryParam

• Severity: medium (CVSS 4.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-20 · updated 2026-10-24
• Weakness: CWE-1321

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.

Affected products

• freescout-help-desk freescout: before 1.8.223

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

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