Eclipse Ditto - Reflected XSS on /ui/ path

Basic information

Project name: Eclipse Ditto

Project id: iot.ditto / https://eclipse.dev/ditto/ / https://github.com/eclipse-ditto/ditto

What are the affected versions?

latest (3.5.5) and probably also below.

Details of the issue

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'). On the url: http://localhost:8080/ui/ javascript code can be executed.

Steps to reproduce

1. run the application
2. navigate to http://localhost:8080/ui/
3. enter </scrip</script>t><img src =q onerror=prompt(8)> to the input in the left corner (cp. Screenshot)

Edit: Even after removing the string from the search input it still triggers every time when switching the environments.

Do you know any mitigations of the issue?

Suitable input validation.