URL-to-PDF and SSRF: how a PDF renderer becomes an attack surface

A renderer that fetches URLs can be pointed at your internal network. The attacks, the defences, and what to demand from a PDF API vendor.

Updated 31 August 2026

A URL-to-PDF endpoint is a web browser you let strangers drive. If that browser sits inside your network, it can be asked to open `http://169.254.169.254/` (cloud metadata), `http://localhost:8080/admin`, or a colleague's dashboard — and print what it sees into a PDF the attacker downloads.

The attack

• Direct: submit an internal URL
• Redirect: submit a public URL that 302s to an internal one
• DNS rebinding: a hostname that resolves publicly the first time and privately the second
• Injected HTML: an `