FreeScout 1.8.206 Patch Bypass for CVE-2026-27636 via Zero-Width Space Character Leads to Remote Code Execution
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
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| freescout-help-desk | freescout | affected |
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No data.
| Vendor | Product | Versions | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Freescout Helpdesk | Freescout |
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No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: 35.1% (35.103% probability within 30 days)
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| References |
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| First Time appeared |
Freescout
Freescout freescout |
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| CPEs | cpe:2.3:a:freescout:freescout:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Freescout
Freescout freescout |
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| Metrics |
ssvc
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| First Time appeared |
Freescout Helpdesk
Freescout Helpdesk freescout |
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| Vendors & Products |
Freescout Helpdesk
Freescout Helpdesk freescout |
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| 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. | |
| Title | FreeScout 1.8.206 Patch Bypass for CVE-2026-27636 via Zero-Width Space Character Leads to Remote Code Execution | |
| Weaknesses | CWE-434 | |
| References |
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| Metrics |
cvssV3_1
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