CVE-2025-54366: freescout Insecure Deserialization

Description

FreeScout is a lightweight free open source help desk and shared inbox built with PHP (Laravel framework). In versions 1.8.185 and below, there is a critical deserialization vulnerability in the /conversation/ajax endpoint that allows authenticated users with knowledge of the APP_KEY to achieve remote code execution. The vulnerability occurs when the application processes the attachments_all and attachments POST parameters through the insecure Helper::decrypt() function, which performs unsafe deserialization of user-controlled data without proper validation. This flaw enables attackers to create arbitrary objects and manipulate their properties, leading to complete compromise of the web application. This is fixed in version 1.8.186.

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CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-502 Deserialization of Untrusted Data

Affected Products

Vendor	Product	Versions
freescout	freescout	< 1.8.86

References

Advisories & Patches

https://github.com/freescout-help-desk/freescout/commit/9669c57f1ddbee896752d9e16270abfd97b20eb9 https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-vcc2-6r66-gvvj

Exploits

https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-vcc2-6r66-gvvj

Frequently Asked Questions

What is CVE-2025-54366? +

FreeScout is a lightweight free open source help desk and shared inbox built with PHP (Laravel framework). In versions 1.8.185 and below, there is a critical deserialization vulnerability in the /conversation/ajax endpoint that allows authenticated users with knowledge of the APP_KEY to achieve remote code execution. The vulnerability occurs when the application processes the attachments_all and attachments POST parameters through the insecure Helper::decrypt() function, which performs unsafe deserialization of user-controlled data without proper validation. This flaw enables attackers to create arbitrary objects and manipulate their properties, leading to complete compromise of the web application. This is fixed in version 1.8.186. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2025-54366? +

CVE-2025-54366 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-54366? +

CVE-2025-54366 affects products from freescout, specifically: freescout. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-54366? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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