WeasyPrint helps web developers to create PDF documents. Prior to version 68.0, a server-side request forgery (SSRF) protection bypass exists in WeasyPrint's default_url_fetcher. The vulnerability allows attackers to access internal network resources (such as localhost services or cloud metadata endpoints) even when a developer has implemented a custom url_fetcher to block such access. This occurs because the underlying urllib library follows HTTP redirects automatically without re-validating the new destination against the developer's security policy. Version 68.0 contains a patch for the issue.