CVE-2026-28289
HIGH WAF: Medium
CVSS 8.1
Published: 2026-03-03
CWE-434
FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. A patch bypass vulnerability for CVE-2026-27636 in FreeScout 1.8.206 and earlier allows any authenticated user with file upload permissions to achieve Remote Code Execution (RCE) on the server by uploading a malicious .htaccess file using a zero-width space character prefix to bypass the security check. The vulnerability exists in the sanitizeUploadedFileName() function in app/Http/Helper.php. The function contains a Time-of-Check to Time-of-Use (TOCTOU) flaw where the dot-prefix check occurs before sanitization removes invisible characters. This vulnerability is fixed in 1.8.207.
WAF Coverage Analysis
Unrestricted File Upload
Medium WAF Coverage
OWASP: A04:2021 Insecure Design
930xxx - Local File Inclusion
Affected Software
| Vendor | Product | Version |
|---|---|---|
| freescout | freescout | up to 1.8.207 |
References
- github.com (Patch)
- github.com (Exploit, Mitigation, Vendor Advisory)
- www.ox.security (Exploit, Vendor Advisory)