CVE-2025-58163
Published: 03 September 2025
Summary
CVE-2025-58163 is a high-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Freescout Freescout. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 20.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly mitigates the deserialization vulnerability by requiring timely remediation through patching to FreeScout version 1.8.186.
Prevents exploitation by enforcing validation of untrusted inputs like customer_id and timestamp parameters before decryption and deserialization in app/Helper.php.
Enables identification of ongoing or successful remote code execution attacks via monitoring for anomalous system behavior on the affected endpoints.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Direct RCE via unauthenticated deserialization in a public-facing web application (Laravel endpoint).
NVD 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.…
more
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.
Deeper analysisAI
CVE-2025-58163 is a deserialization of untrusted data vulnerability (CWE-502) affecting FreeScout, an open-source help desk and shared inbox application built on PHP's Laravel framework. The issue impacts versions 1.8.185 and earlier, where the endpoint `/help/{mailbox_id}/auth/{customer_id}/{hash}/{timestamp}` processes the `customer_id` and `timestamp` parameters through the `decrypt` function in `app/Helper.php` without proper validation. This decrypts the input using Laravel's built-in encryption functions and subsequently deserializes the payload without sanitization, enabling the execution of malicious serialized PHP objects.
Authenticated attackers with knowledge of the application's APP_KEY can exploit this vulnerability remotely over the network with low complexity and no user interaction required (CVSSv3.1 score of 8.8: AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H). By crafting a malicious `customer_id` or `timestamp` containing serialized PHP objects, they can trigger arbitrary command execution on the server, potentially leading to full compromise of the affected FreeScout instance.
The vulnerability is fixed in FreeScout version 1.8.186, as detailed in the project's security advisory (GHSA-j94w-q9gj-c37g), release notes, and the patching commit (e2de65f3f32f825b4ec5558643ed81438c9a6bc6). Security practitioners should upgrade to the patched version immediately and review access to the APP_KEY, which must remain confidential to prevent exploitation.
Details
- CWE(s)