Apache NiFi External XML Entity issue in SplitXML processor. Malicious XML content could cause information disclosure or remote code execution. The fix to disable external general entity parsing and disallow doctype declarations was applied on the Apache NiFi 1.6.0 release. Users running a prior 1.x release should upgrade to the appropriate release.

Any authenticated user (valid client certificate but without ACL permissions) could upload a template which contained malicious code and caused a denial of service via Java deserialization attack. The fix to properly handle Java deserialization was applied on the Apache NiFi 1.4.0 release. Users running a prior 1.x release should upgrade to the appropriate release.

A malicious X-ProxyContextPath or X-Forwarded-Context header containing external resources or embedded code could cause remote code execution. The fix to properly handle these headers was applied on the Apache NiFi 1.5.0 release. Users running a prior 1.x release should upgrade to the appropriate release.

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.