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 8.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 18.7% 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).
Deeper analysis
FreeScout versions 1.8.185 and earlier contain a deserialization of untrusted data vulnerability (CWE-502) in the PHP Laravel-based help desk application. The flaw resides in the decrypt function within app/Helper.php, which processes the customer_id and timestamp parameters from the endpoint /help/{mailbox_id}/auth/{customer_id}/{hash}/{timestamp} using Laravel's built-in encryption routines and then deserializes the resulting payload without validation or sanitization.
Authenticated attackers who possess the application's APP_KEY can supply a malicious serialized PHP object through this endpoint to trigger arbitrary command execution and achieve remote code execution on the server.
The vulnerability is addressed in version 1.8.186. The project has published a corresponding security advisory, release tag, and commit that removes the unsafe deserialization path.
EPSS remains low and unchanged at a peak of 0.0147 with no material increase after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-26476
Vulnerability details
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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Direct RCE via unauthenticated deserialization in a public-facing web application (Laravel endpoint).
CVEs Like This One
Affected Assets
Mitigating Controls
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.