Frappe Builder versions before 1.36.1 contain a server-side request forgery vulnerability in the convert_to_webp API endpoint, which lacks the has_page_write access control applied to similar asset-ingest handlers and performs an unprotected requests.get call that follows redirects without re-validating resolved IP addresses. A low-privilege authenticated user can supply an image_url pointing to an internal address or use DNS rebinding and open redirects to make the server fetch internal network resources or cloud metadata endpoints, with successful image responses saved to a world-readable /files/ URL enabling data exfiltration or blind probing of internal hosts.