The vulnerability CVE-2026-44694 affects n8n-mcp versions >= 2.18.7 and < 2.50.2. It is a TOCTOU race condition combined with an authenticated SSRF vulnerability impacting webhook trigger tools, the n8n API client (N8N_API_URL), and URLs supplied via the x-n8n-url header in multi-tenant HTTP mode. This allows an authenticated user with low privileges to potentially manipulate server-side requests during a race window, leading to SSRF attacks. The issue has been addressed and patched in version 2.50.2. No public exploits are currently known.

Successful exploitation could allow an authenticated user with low privileges to perform server-side request forgery attacks, potentially leading to unauthorized internal network access or information disclosure. The vulnerability arises from a race condition in the handling of URLs used by webhook triggers and API client requests in multi-tenant environments. The CVSS 4.0 score of 7.2 reflects a high impact with network attack vector, requiring low privileges but no user interaction.

A patch addressing this vulnerability is available in n8n-mcp version 2.50.2. Users should upgrade to version 2.50.2 or later to remediate this issue. Since this is not a cloud service, remediation requires applying the vendor's update. No additional vendor advisory content is provided, so check the vendor's official channels for the latest guidance.