CVE-2026-27636: CVE-2026-27636: FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior t…
freescout · freescout · NVD published 2026-02-25 · posted 2026-03-01 · last modified 2026-06-17
What it is
FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.206, FreeScout's file upload restriction list in `app/Misc/Helper.php` does not include `.htaccess` or `.user.ini` files. On Apache servers with `AllowOverride All` (a common configuration), an authenticated user can upload a `.htaccess` file to redefine how files are processed, enabling Remote Code Execution. This vulnerability can be exploited on its own or in combination with CVE-2026-27637. Version 1.8.206 fixes both vulnerabilities.
| Weakness | CWE-434 |
|---|---|
| CVSS vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (source: [email protected]) |
| ATT&CK tactics | Initial Access → Execution → Persistence |
Exploitation evidence
First exploit evidence seen: 2026-03-01 (earliest date across the sources below).
Exploited in the wild
No source on this site lists in-the-wild exploitation yet (CISA KEV, VulnCheck KEV).
Public exploit code
Metasploit
exploit/multi/http/freescout_htaccess_rce: FreeScout Unauthenticated RCE via ZWSP .htaccess Bypass (disclosure 2026-03-01)
GitHub proof-of-concept repositories below quality bar
1 public repositories from 1 accounts, first seen 2026-03-04.
Verify before running: public PoCs can be malicious. Read the code and only run it in an isolated lab. A PoC means exploit code is public, not that this CVE is exploited in the wild.
Sources: Rapid7 Metasploit Framework module metadata · nomi-sec/PoC-in-GitHub.
Defend the Chain
The attack chain for CVE-2026-27636 laid across the MITRE ATT&CK Enterprise tactics. Solid cards come from the MITRE CTID KEV mappings; dashed cards are inferred by CVERadar from the CWE or description. Correct defences are real ATT&CK mitigations for that technique.
Pick a red technique card on the board, then choose the defence that stops it.
Defend against T1190 Exploit Public-Facing Application Inferred
Inferred from CWE CWE-434
How to fix it
Fixed versions
- freescout freescout: upgrade to 1.8.206 or later
Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.
Vendor advisories and patches
- https://github.com/freescout-help-desk/freescout/commit/9984071e6f1b4e633fdcffcea82bbebc9c1e009c (Patch)
- https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-mw88-x7j3-74vc (Exploit, Vendor Advisory)
MITRE ATT&CK mitigations for this chain
- M1048 Application Isolation and Sandboxing (for T1190, T1203) : Application isolation will limit what other processes and system features the exploited target can access.
- M1037 Filter Network Traffic (for T1190) : Restrict outbound network traffic from public-facing servers to prevent unauthorized connections from initiating communications with attacker-controlled infrastructure. While this may not prevent the initial exploitation, it limits the attacker's ability to verify and control the compromised server post-exploit, reduci
- M1030 Network Segmentation (for T1190) : Segment externally facing servers and services from the rest of the network with a DMZ or on separate hosting infrastructure.
- M1016 Vulnerability Scanning (for T1190) : Regularly scan externally facing systems for vulnerabilities and establish procedures to rapidly patch systems when critical vulnerabilities are discovered through scanning and through public disclosure.
- M1026 Privileged Account Management (for T1190) : Use least privilege for service accounts will limit what permissions the exploited process gets on the rest of the system.
- M1050 Exploit Protection (for T1190, T1203) : Web Application Firewalls may be used to limit exposure of applications to prevent exploit traffic from reaching the application.
- M1035 Limit Access to Resource Over Network (for T1190) : Ensure that all publicly exposed services are actually intended to be so, and restrict access to any that should only be available internally.
- M1051 Update Software (for T1190, T1203) : Update software regularly by employing patch management for externally exposed applications.
- M1042 Disable or Remove Feature or Program (for T1505.003) : Consider disabling functions from web technologies such as PHP’s `evaI()` that may be abused for web shells.
- M1018 User Account Management (for T1505.003) : Enforce the principle of least privilege by limiting privileges of user accounts so only authorized accounts can modify the web directory.
Detection Generic guidance
- Initial Access: Alert on unusual requests to the affected service (odd paths, oversized payloads, exploit strings) in WAF, reverse-proxy and application logs.
- Execution: Watch for the service process spawning shells or script interpreters (cmd.exe, powershell, sh, bash, python) via EDR process-tree rules.
- Persistence: Look for new files in web roots, new scheduled tasks/services, and new accounts created after the exposure window.
Response checklist Generic guidance
- Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
- Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
- Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
- Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.