Vulnerability Description
FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.224, the denylist that neutralizes dangerous file uploads (`Helper::$restricted_extensions`) is incomplete: it does not cover the `.pht` extension. The authenticated upload endpoint `POST /uploads/upload` (`SecureController@upload`) stores files with their original extension into the web-accessible directory `storage/app/public/uploads/` (served at `/storage/uploads/`). On the standard Apache + `libapache2-mod-php` deployment, the default handler `<FilesMatch ".+\.ph(ar|p[3457]?|t|tml)$">` executes `.pht`, so **any authenticated agent can upload a `.pht` web shell and run arbitrary commands as the web-server user** (`www-data`). This is a direct bypass of the fix for CVE-2025-48471, which added `phtml`/`phar` but not `pht` (nor `phtm`, `phps`). Version 1.8.224 contains an updated fix.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-27vp-f
- https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-27vp-f
FAQ
What is CVE-2026-53593?
CVE-2026-53593 is a vulnerability with a CVSS score of 8.8 (HIGH). FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.224, the denylist that neutralizes dangerous file uploads (`Helper::$restricted_extensions`) is ...
How severe is CVE-2026-53593?
CVE-2026-53593 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-53593?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.