Improper escaping of database table names in the CaptureChangeMySQL Processor included with Apache NiFi 1.2.0 through 2.9.0 allows for injecting SQL commands using crafted naming. Manual quoted boundaries added in Apache NiFi 1.8.0 narrowed the scope of potential injection options, but did not cover additional strategies. Apache NiFi installations that do not use the CaptureChangeMySQL Processor are not subject to this vulnerability. Upgrading to Apache NiFi 2.10.0 is the recommended mitigation, which incorporates more robust identifier escaping.
An authorized user could upload a template which contained malicious code and accessed sensitive files via an XML External Entity (XXE) attack. The fix to properly handle XML External Entities was applied on the Apache NiFi 1.4.0 release. Users running a prior 1.x release should upgrade to the appropriate release.
In Apache NiFi before 0.7.4 and 1.x before 1.3.0, there are certain user input components in the UI which had been guarding for some forms of XSS issues but were insufficient.