XSS via Embedded SVG in SVG Diagram Format in GitHub repository plantuml/plantuml prior to 1.2022.4. Stored XSS in the context of the diagram embedder. Depending on the actual context, this ranges from stealing secrets to account hijacking or even to code execution for example in desktop applications. Web based applications are the ones most affected. Since the SVG format allows clickable links in diagrams, it is commonly used in plugins for web based projects (like the Confluence plugin, etc. see https://plantuml.com/de/running).

URL Restriction Bypass in GitHub repository plantuml/plantuml prior to V1.2022.5. An attacker can abuse this to bypass URL restrictions that are imposed by the different security profiles and achieve server side request forgery (SSRF). This allows accessing restricted internal resources/servers or sending requests to third party servers.