CVE-2018-25045: Django REST framework XSS Vulnerability

The vulnerability stemmed from two key factors:

1. The base.html template explicitly disabled autoescaping via {% autoescape off %} around the response rendering logic, which removed Django's default XSS protections.
2. The urlize_quoted_links filter's pre-patch implementation did not properly enforce escaping in autoescape-disabled contexts. It relied on manual escaping checks (safe_input and autoescape flags) but failed to ensure all user-controlled content was sanitized when autoescape was globally disabled in the template.

The combination of these two factors allowed untrusted input (e.g., content or response_headers values) to render without escaping. The commit diff shows the removal of {% autoescape off %} in base.html and fixes to urlize_quoted_links to use a unified conditional_escape helper, ensuring proper escaping regardless of the autoescape context.