There are 3 open security issues in bullseye.
3 issues left for the package maintainer to handle:
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).
Improper Access Control in GitHub repository plantuml/plantuml prior to 1.2023.9.
Server-Side Request Forgery (SSRF) in GitHub repository plantuml/plantuml prior to 1.2023.9.
You can find information about how to handle these issues in the security team's documentation.