Netdata before 2.3.1 reflects the user-supplied love query parameter of the api/v2/ilove.svg and api/v3/ilove.svg endpoints verbatim into the generated SVG document (into a text element) without HTML or XML escaping, and serves the response with Content-Type image/svg+xml. An attacker can craft a URL such as /api/v2/ilove.svg?love=<script>...</script>; when a victim navigates to it the injected script executes in the victim browser in the origin of the Netdata instance (reflected cross-site scripting). These endpoints are registered with HTTPACLNOCHECK and anonymous access and, because bearer-token protection is disabled by default, are reachable without authentication on a default Netdata agent. The issue was resolved by removing the ilove endpoint.