DataLens is a business intelligence and data visualization system. A specifically crafted request allowed the creation of a special chart type with the ability to pass custom javascript code that would later be executed in an unprotected sandbox on subsequent requests to that chart. The problem was fixed in the datalens-ui version `0.1449.0`. Restricting access to the API for creating or modifying charts (`/charts/api/charts/v1/`) would mitigate the issue.
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.