In Apache NiFi before 0.7.2 and 1.x before 1.1.2 in a cluster environment, if an anonymous user request is replicated to another node, the originating node identity is used rather than the "anonymous" user.

Apache NiFi 0.7.0 through 1.23.2 include the JoltTransformJSON Processor, which provides an advanced configuration user interface that is vulnerable to DOM-based cross-site scripting. If an authenticated user, who is authorized to configure a JoltTransformJSON Processor, visits a crafted URL, then arbitrary JavaScript code can be executed within the session context of the authenticated user. Upgrading to Apache NiFi 1.24.0 or 2.0.0-M1 is the recommended mitigation.