CVE-2026-53593: CWE-434: Unrestricted Upload of File with Dangerous Type in freescout-help-desk freescout
FreeScout versions prior to 1.8.224 have an incomplete denylist for dangerous file uploads, missing the .pht extension. Authenticated users can upload .pht files, which are executed by default Apache PHP handlers, allowing remote code execution as the web server user. This vulnerability bypasses a previous fix that did not cover .pht files. Version 1.8.224 includes an updated fix to address this issue.
AI Analysis
Technical Summary
CVE-2026-53593 is a vulnerability in FreeScout help desk software where the file upload denylist does not include the .pht extension. Authenticated users can upload .pht files to a web-accessible directory, which Apache with mod_php executes as PHP scripts. This allows arbitrary command execution as the web server user (www-data). The issue is a direct bypass of a prior fix for CVE-2025-48471, which missed .pht files. The vulnerability affects all FreeScout versions before 1.8.224, which contains the updated fix.
Potential Impact
An authenticated attacker can upload a .pht web shell and execute arbitrary commands with the privileges of the web server user, leading to full compromise of the affected system. This results in high confidentiality, integrity, and availability impact.
Mitigation Recommendations
Upgrade FreeScout to version 1.8.224 or later, which includes the updated fix for this vulnerability by extending the denylist to cover the .pht extension. No other mitigation is indicated by the vendor advisory. Patch status is not explicitly stated but the updated fix in 1.8.224 implies an official fix is available.
CVE-2026-53593: CWE-434: Unrestricted Upload of File with Dangerous Type in freescout-help-desk freescout
Description
FreeScout versions prior to 1.8.224 have an incomplete denylist for dangerous file uploads, missing the .pht extension. Authenticated users can upload .pht files, which are executed by default Apache PHP handlers, allowing remote code execution as the web server user. This vulnerability bypasses a previous fix that did not cover .pht files. Version 1.8.224 includes an updated fix to address this issue.
CVSS v3.1
Score 8.8high
Affected software
pkg:github/freescout-help-desk/freescoutRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-53593 is a vulnerability in FreeScout help desk software where the file upload denylist does not include the .pht extension. Authenticated users can upload .pht files to a web-accessible directory, which Apache with mod_php executes as PHP scripts. This allows arbitrary command execution as the web server user (www-data). The issue is a direct bypass of a prior fix for CVE-2025-48471, which missed .pht files. The vulnerability affects all FreeScout versions before 1.8.224, which contains the updated fix.
Potential Impact
An authenticated attacker can upload a .pht web shell and execute arbitrary commands with the privileges of the web server user, leading to full compromise of the affected system. This results in high confidentiality, integrity, and availability impact.
Mitigation Recommendations
Upgrade FreeScout to version 1.8.224 or later, which includes the updated fix for this vulnerability by extending the denylist to cover the .pht extension. No other mitigation is indicated by the vendor advisory. Patch status is not explicitly stated but the updated fix in 1.8.224 implies an official fix is available.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-09T19:39:52.403Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a5e7dae2a4a8d5989a50e02
Added to database: 07/20/2026, 19:57:34 UTC
Last enriched: 07/20/2026, 20:12:05 UTC
Last updated: 07/21/2026, 03:47:40 UTC
Views: 11
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