An XSS vulnerability was found in ovirt-engine when submitting configuration file used to build up the VNC/SPICE-Connection. The file is automatically generated without any user input on the client side and uploaded to the server, which immediately reflects that upload. Legitimate HTTP Request looks aas following:

POST /ovirt-engine/services/attachment/console.vv

contenttype=application%2Fx-virt-viewer%3B+charset%3DUTF-8&content=[...configuration
file...]&encodingtype=plain

Web application accepts the POST-Parameter contenttype, that sets the Content-Type of the HTTP-Response of the reflected upload. When setting the contenttype to text/html, it allows to inject malicious JavaScript code to be reflected on the page. The attacker could send RPC-Requests via XHR with the privileges of the victim. If the victim is logged in, the attacker can inject a JavaScript code that sends a RPC-Request to start, stop or manipulate a specific VM.