FreeScout up to 1.8.222 getQueryParam public/js/main.js prototype pollution

Summaryinfo

A vulnerability classified as critical was found in FreeScout up to 1.8.222. Affected by this issue is some unknown functionality of the file public/js/main.js of the component getQueryParam. Such manipulation leads to prototype pollution. This vulnerability is traded as CVE-2026-53592. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in FreeScout up to 1.8.222. It has been rated as critical. Affected by this issue is an unknown function of the file public/js/main.js of the component getQueryParam. The manipulation with an unknown input leads to a prototype pollution vulnerability. Using CWE to declare the problem leads to CWE-1321. The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-53592 since 06/09/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.

Upgrading to version 1.8.223 eliminates this vulnerability.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Name

• FreeScout

Version

• 1.8.222

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion