Medium · published October 30, 2026
Stirling-PDF is a locally hosted web application that facilitates various operations on PDF files. From 2.13.1 until 2.13.2, the POST /api/v1/convert/svg/pdf endpoint renders attacker-supplied SVG through Apache Batik, and a scheme-less root-relative image reference bypasses SvgSanitizer.isExternalUrl() before Batik resolves it against the file:///input.svg document base as a same-origin local file. The convert() and addSvgAsPage() paths in app/core/src/main/java/stirling/software/SPDF/utils/SvgToPdf.java can then render image-decodable server files into the returned PDF when sanitization is enabled, including without authentication on login-disabled deployments or with non-admin access when login is enabled. The issue discloses PNG, JPG, GIF, or SVG content and provides an existence oracle only for image-decodable paths; plain text, binary files, directories, XInclude text, external entities, explicit file URLs, and tested HTTP references are not disclosed through this mechanism. This issue is fixed in version 2.13.2.