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CVE-2026-28289

CRITICAL
10.0
CVSS 3.1
Description
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.

Metadata

CVE ID
CVE-2026-28289
State
PUBLISHED
Assigner
GitHub_M
Reserved
2026-02-26 01:52 UTC
Published
2026-03-03 22:59 UTC
Last updated
2026-03-05 21:09 UTC
Primary CWE
CWE-434
CWE-434: Unrestricted Upload of File with Dangerous Type
Vendor / Product
freescout-help-desk / freescout
Sources
cve.org  ·  NVD

Severity & Metrics

10.0 CRITICAL CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
SSVC — CISA Coordinator
Exploitation
none
Automatable
yes
Tech. Impact
total
Affected products (1)
VendorProductPlatformVersions
freescout-help-desk freescout — < 1.8.207
Weakness (CWE)
CWESourceDescription
CWE-434 cna CWE-434: Unrestricted Upload of File with Dangerous Type
CVSS scores (1)
ScoreSeverityVersionSourceVector
10.0 CRITICAL 3.1 cna CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
References (2)
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