Hitachi Vantara Pentaho Data Integration & Analytics versions before 10.2.0.6, including 9.3.x and 8.3.x, do not restrict Groovy scripts in new PRPT reports published by users, allowing insertion of arbitrary scripts and leading to a RCE.
Credits
Nir Zadok (nirza) and Moshe Siman Tov Bustan from OX Security