CVE-2026-55073: weasyprint Has Server-Side Request Forgery (SSRF)

url_fetcher is WeasyPrint’s documented mechanism for restricting resource loading - applications use it to block file://, internal hosts, etc. when rendering untrusted input.

Two write_pdf() channels ignore the document’s url_fetcher and build a fresh default URLFetcher() instead. A restrictive fetcher set on HTML() is silently bypassed for:

• xmp_metadata=[url] - the URL is fetched and the bytes are embedded verbatim in the output PDF. This is an arbitrary local file read when the path is attacker-influenced.
• stylesheets=[url_or_path] - the sheet is fetched and applied. This is SSRF / arbitrary local-or-internal resource loading, and it is transitive: the permissive fetcher propagates through the whole @import / url() graph.

Applications affected are those that (1) run WeasyPrint server-side, (2) set a restrictive url_fetcher to block file:// or internal hosts, and (3) forward an attacker-influenced URL/path into either parameter - e.g. PDF rendering APIs, invoice/report generators, document SaaS.