CVE-2025-58163: FreeScout's deserialization of untrusted data can lead to Remote Code Execution

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2025-09-03 · updated 2026-10-19
Weakness: CWE-502

Description

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Versions 1.8.185 and earlier contain a deserialization of untrusted data vulnerability that allows authenticated attackers with knowledge of the application's APP_KEY to achieve remote code execution. The vulnerability is exploited via endpoint, e.g.: `/help/{mailbox_id}/auth/{customer_id}/{hash}/{timestamp}` where the `customer_id` and `timestamp` parameters are processed through the decrypt function in `app/Helper.php` without proper validation. The code decrypts using Laravel's built-in encryption functions, which subsequently deserialize the decrypted payload without sanitization, allowing attackers to craft malicious serialized PHP objects using classes to trigger arbitrary command execution. This is fixed in version 1.8.186.

Affected products

freescout-help-desk freescout: before 1.8.186 — fixed in 1.8.186

How to fix

Upgrade to a fixed version: freescout-help-desk freescout 1.8.186. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2025-58163 or the next vulnerability affects your stack