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.
https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-j94w-q9gj-c37g
https://github.com/freescout-help-desk/freescout/releases/tag/1.8.186
https://github.com/freescout-help-desk/freescout/commit/e2de65f3f32f825b4ec5558643ed81438c9a6bc6
Published: 2025-09-03
Updated: 2025-09-04
Base Score: 6.5
Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:P
Severity: Medium
Base Score: 8.8
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity: High
Base Score: 8.6
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.00062