CVE-2024-34698: Prototype Pollution in getQueryParam Function (URL Query Parser)

Severity: medium (CVSS 6.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2024-05-14 · updated 2026-06-17
Weakness: CWE-1321

Description

FreeScout is a free, self-hosted help desk and shared mailbox. Versions of FreeScout prior to 1.8.139 contain a Prototype Pollution vulnerability in the `/public/js/main.js` source file. The Prototype Pollution arises because the `getQueryParam` Function recursively merges an object containing user-controllable properties into an existing object (For URL Query Parameters Parsing), without first sanitizing the keys. This can allow an attacker to inject a property with a key `__proto__`, along with arbitrarily nested properties. The merge operation assigns the nested properties to the `params` object's prototype instead of the target object itself. As a result, the attacker can pollute the prototype with properties containing harmful values, which are then inherited by user-defined objects and subsequently used by the application dangerously. The vulnerability lets an attacker control properties of objects that would otherwise be inaccessible. If the application subsequently handles an attacker-controlled property in an unsafe way, this can potentially be chained with other vulnerabilities like DOM-based XSS, Open Redirection, Cookie Manipulation, Link Manipulation, HTML Injection, etc. Version 1.8.139 contains a patch for the issue.

Affected products

freescout-help-desk freescout: before 1.8.139 — fixed in 1.8.139

How to fix

Upgrade to a fixed version: freescout-help-desk freescout 1.8.139. Check the vendor advisory for mitigations.

References

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