GHSA-2x35-3fw4-9jr4: n8n: Send Email Node Arbitrary File Read and SSRF via Nodemailer Content-Object Type Confusion

The n8n Send Email node did not enforce that its message fields were strings, so a crafted untrusted non-string value from a workflow expression could be treated by the underlying mail library as a file path or URL. This could allow disclosure of local files on the n8n host.

Exploitation requires a pre-existing active workflow with an unauthenticated webhook, valid SMTP credentials configured on the Send Email node, and untrusted input mapped directly into the text or HTML body field. This is not a default n8n configuration.