The vulnerability stems from session keys being rendered in HTML templates. The key evidence is in the commit diff showing removal of session_key references from session_list.html. The view responsible for rendering this template (likely a ListView subclass) and the template itself both contributed to the exposure. While no specific view function is shown in diffs, Django's pattern of URL 'user_sessions:session_list' implies a corresponding view that renders the vulnerable template. The high confidence comes from the direct template modification in the patch and test updates verifying session key removal.