CVE-2026-28289
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…
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 35.1%, higher than 98% of all known CVEs. Patch or mitigate before the next change window.
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.
- CVSS 3.1
- 8.1 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 35.10% probability · 98th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-434
- Affected
- freescout/freescout
- Source
- security-advisories@github.com
EPSS moved from 2.6% on 24 September 2026 to 35.1% on 30 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
References
- https://github.com/freescout-help-desk/freescout/commit/f7bc16c56a6b13c06da52ad51fd666546b40818fPatch
- https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-5gpc-65p8-ffwpExploit, Mitigation, Vendor Advisory
- https://www.ox.security/blog/freescout-rce-cve-2026-28289/Exploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.