Medium · published October 30, 2026
Stirling-PDF is a locally hosted web application that facilitates various operations on PDF files. Prior to 3.0.0, POST /api/v1/ai/tools/create-pdf-from-html-agent accepts attacker-controlled htmlContent and passes it to WeasyPrint without CustomHtmlSanitizer, unlike the sanitized /api/v1/convert/html/pdf control path. HTTP and HTTPS resource references can make server-side requests to internal or cloud-metadata destinations, while file references can embed local content readable by the Stirling-PDF process into the generated PDF. The endpoint is reachable without credentials when security.enableLogin is false, and the flaw is distinct from earlier Stirling-PDF WeasyPrint vulnerabilities in older conversion paths. This issue is fixed in version 3.0.0.