The Kyuubi Engine UI proxy accepts a host and port from the request path and forwards HTTP requests to that destination. This improper restriction of communication channels (CWE-923) enables remote attackers with network access to the proxy to induce the Kyuubi server to send HTTP requests to arbitrary reachable hosts, resulting in SSRF or open-proxy behavior. The issue affects Apache Kyuubi versions from 1.8.0 up to but not including 1.12.0. The vendor fixed this by disabling the proxy by default in version 1.12.0 and requiring explicit enabling and host whitelisting via configuration parameters.

An attacker with network access to the vulnerable Kyuubi Engine UI proxy can cause the server to send HTTP requests to arbitrary hosts, potentially allowing SSRF attacks or misuse of the server as an open proxy. This can lead to information disclosure, unauthorized internal network access, or other impacts depending on the attacker's goals and network environment.

Users should upgrade to Apache Kyuubi version 1.12.0 or later, where the Engine UI proxy is disabled by default. If proxy functionality is required, it must be explicitly enabled by setting 'kyuubi.frontend.rest.engine.ui.proxy.enabled=true' and restricting allowed target hosts using 'kyuubi.frontend.rest.engine.ui.proxy.hosts' configuration. This mitigates the risk by limiting proxy targets and reducing exposure.