GHSA-qqhf-xfhw-7884: Markdownify has Files or Directories Accessible to External Parties

Markdownify version 1.4.1 allows an external attacker to remotely obtain arbitrary local files on any client that attempts to view a malicious markdown file through Markdownify. This is possible because the application does not have a CSP policy (or at least not strict enough) and/or does not properly validate the contents of markdown files before rendering them.