Apache NiFi 1.16.0 through 1.28.0 and 2.0.0-M1 through 2.0.0-M4 include optional debug logging of Parameter Context values during the flow synchronization process. An authorized administrator with access to change logging levels could enable debug logging for framework flow synchronization, causing the application to write Parameter names and values to the application log. Parameter Context values may contain sensitive information depending on application flow configuration. Deployments of Apache NiFi with the default Logback configuration do not log Parameter Context values. Upgrading to Apache NiFi 2.0.0 or 1.28.1 is the recommendation mitigation, eliminating Parameter value logging from the flow synchronization process regardless of the Logback configuration.

Multiple components in Apache NiFi 0.0.1 to 1.16.0 do not restrict XML External Entity references in the default configuration. The Standard Content Viewer service attempts to resolve XML External Entity references when viewing formatted XML files. The following Processors attempt to resolve XML External Entity references when configured with default property values: - EvaluateXPath - EvaluateXQuery - ValidateXml Apache NiFi flow configurations that include these Processors are vulnerable to malicious XML documents that contain Document Type Declarations with XML External Entity references. The resolution disables Document Type Declarations in the default configuration for these Processors, and disallows XML External Entity resolution in standard services.