A malicious host header in an incoming HTTP request could cause NiFi to load resources from an external server. The fix to sanitize host headers and compare to a controlled whitelist was applied on the Apache NiFi 1.5.0 release. Users running a prior 1.x release should upgrade to the appropriate release.
In Apache NiFi before 1.0.1 and 1.1.x before 1.1.1, there is a cross-site scripting vulnerability in connection details dialog when accessed by an authorized user. The user supplied text was not being properly handled when added to the DOM.