Open WebUI: Blind server side request forgery (SSRF) via the PDF generate function

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.5.11, there is a blind server side request forgery (SSRF) via the PDF generate function. In the PDF export, user inputs are interpreted as HTML and embedded into the PDF. According to tests, scripts and some potentially dangerous tags (iFrame, Object, etc.) are blocked, preventing server-side content from being read through this vulnerability. However, an image tag can be used to force a server-side request (SSRF), as shown in the following below. This vulnerability is fixed in 0.5.11.