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Fencer Vulns
medium 4.6

CVE-2024-34698 json

Prototype Pollution in getQueryParam Function (URL Query Parser)

published 2024-05-13 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-34994

cvss
4.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

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.

Patch / fix

  • freescout_helpdesk freescout 1.8.139

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/freescout-helpdesk/freescout/security/advisories/GHSA-rx6j-4c33-9h3r referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.6 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L
NVD 3.1 6.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

Affected products

  • freescout-helpdesk freescout
  • freescout_helpdesk freescout

Classification

Weakness
  • CWE-1321 Improperly Controlled Modification of Object Prototype Attributes

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.