# CVE-2026-40566

> Vulnerability · severity: **MEDIUM** (CVSS 4.1).

## Description

FreeScout is a free self-hosted help desk and shared mailbox. Versions prior to 1.8.213 have a Server-Side Request Forgery (SSRF) vulnerability in the IMAP/SMTP connection test functionality of FreeScout's `MailboxesController`. Three AJAX actions  `fetch_test` (line 731), `send_test` (line 682), and `imap_folders` (line 773) in `app/Http/Controllers/MailboxesController.php`  pass admin-configured `in_server`/`in_port` and `out_server`/`out_port` values directly to `fsockopen()` via `Helper::checkPort()` and to IMAP/SMTP client connections with zero SSRF protection. There is no IP validation, no hostname restriction, no blocklist of internal ranges, and no call to the project's own `sanitizeRemoteUrl()` or `checkUrlIpAndHost()` functions. The validation block in `connectionIncomingSave()` is entirely commented out. An authenticated admin can configure a mailbox's IMAP or SMTP server to point at any internal host and port, then trigger a connection test. The server opens raw TCP connections (via `fsockopen()`) and protocol-level connections (via IMAP client or SMTP transport) to the attacker-specified target. The response differentiates open from closed ports, enabling internal network port scanning. When the IMAP client connects to a non-IMAP service, the target's service banner or error response is captured in the IMAP debug log and returned in the AJAX response's `log` field, making this a semi-blind SSRF that enables service fingerprinting. In cloud environments, the metadata endpoint at `169[.]254[.]169[.]254` can be probed and partial response data may be leaked through protocol error messages. This is distinct from the `sanitizeRemoteUrl()` redirect bypass (freescout-3) -- different code path, different root cause, different protocol layer. Version 1.8.213 patches the vulnerability.

## Key facts

- **CVE ID:** CVE-2026-40566
- **Published:** 2026-04-21
- **CVSS severity:** MEDIUM
- **CVSS base score:** 4.1
- **CWE codes:** CWE-918

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40566

## Citation

> AI Analytics. CVE-2026-40566. Retrieved 2026-07-20 from https://api.ai-analytics.org/cve/CVE-2026-40566. Derived from NIST NVD. Licensed CC0.

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