Affected: Homebrew: weasyprint

## Summary

`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.

## Affected versions

All versions through current `main` - v69.0, commit `2945986160dedd97a7547be03805b667964e422a`.

## Root cause

`select_source()` defaults to a fresh fetcher when none is passed (`weasyprint/urls.py`):

```python def select_source(guess=None, filename=None, url=None, ..., url_fetcher=None, ...): ... if url_fetcher is None: url_fetcher = URLFetcher() ```

Five of the seven resource-l…

Affected: Kozea WeasyPrint

WeasyPrint helps web developers to create PDF documents. Prior to 70.0, server-side applications that configure a restrictive url_fetcher and pass attacker-influenced values to HTML.write_pdf() can have the restriction bypassed through the xmp_metadata or stylesheets options. In weasyprint/pdf/init.py, xmp_metadata calls select_source() without the document url_fetcher, allowing an accessible local file to be read and embedded verbatim in the output PDF. In weasyprint/document.py, stylesheets constructs CSS() without the document url_fetcher, allowing local or internal resource loading and propagating the permissive fetcher through nested CSS imports and url() references. The stylesheets channel applies fetched resources but does not by itself disclose stylesheet comments verbatim. This issue is fixed in version 70.0.

Affected: PyPI: weasyprint

## Summary

`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.

## Affected versions

All versions through current `main` - v69.0, commit `2945986160dedd97a7547be03805b667964e422a`.

## Root cause

`select_source()` defaults to a fresh fetcher when none is passed (`weasyprint/urls.py`):

```python def select_source(guess=None, filename=None, url=None, ..., url_fetcher=None, ...): ... if url_fetcher is None: url_fetcher = URLFetcher() ```

Five of the seven resource-l…