CVE-2026-53593 Details
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.
A remote code execution vulnerability has been identified in FreeScout versions prior to 1.8.224. The issue arises from an incomplete denylist for file uploads, which fails to include the .pht extension. The vulnerability exists in the authenticated upload endpoint POST /uploads/upload, where files are stored with their original extensions in a web-accessible directory. On standard Apache servers with libapache2-mod-php, .pht files are executed, allowing authenticated users to upload .pht web shells that execute commands as the web server user.
Users are advised to update to FreeScout version 1.8.224 or later, where this vulnerability has been addressed. Additionally, consider implementing a more robust file upload policy that includes an allowlist of permitted extensions and MIME types.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Jul 20, 2026CISA-ADP
Assessed Jul 21, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-27vp-fpg8-j8wv | CISA-ADP | AdvisoryExploitRemedyVendor |
| https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-27vp-fpg8-j8wv | [email protected] | AdvisoryExploitRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-434 | Unrestricted Upload of File with Dangerous Type | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| FreeScout | < 1.8.224 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 21, 2026 | CVE Modified | CISA-ADP |
| Jul 20, 2026 | New CVE Received | [email protected] |