CVE-2026-53592Public exploitNetwork attack vector

Browser object modification via nested query keys

Published Jul 20, 2026 · Updated Jul 20, 2026

Prototype pollution in FreeScout before 1.8.223 allows remote authenticated users to alter browser object properties via a crafted URL. The getQueryParam function in public/js/main.js checks only whether a complete query key begins with proto, then assigns parsed nested segments without rejecting proto in an inner position. A logged-in user must cause another user to open the URL; the resulting Object.prototype properties affect that page's JavaScript context, but no standalone execution gadget is reported.

CVSS severity4.6
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Prototype pollution in FreeScout before 1.8.223 allows remote authenticated users to alter browser object properties via a crafted URL. The getQueryParam function in public/js/main.js checks only whether a complete query key begins with proto, then assigns parsed nested segments without rejecting proto in an inner position. A logged-in user must cause another user to open the URL; the resulting Object.prototype properties affect that page's JavaScript context, but no standalone execution gadget is reported.

The record

CVE
CVE-2026-53592
Published
Jul 20, 2026
Updated
Jul 20, 2026
Vendor
FreeScout
Product
FreeScout
Classifications
CWE-1321, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.8.223

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

FreeScout · FreeScoutversion=< 1.8.223

Published CVSS scores

4.6GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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