Apache Hadoop 0.23.x before 0.23.11 and 2.x before 2.4.1, as used in Cloudera CDH 5.0.x before 5.0.2, do not check authorization for the (1) refreshNamenodes, (2) deleteBlockPool, and (3) shutdownDatanode HDFS admin commands, which allows remote authenticated users to cause a denial of service (DataNodes shutdown) or perform unnecessary operations by issuing a command.

The Kerberos/MapReduce security functionality in Apache Hadoop 0.20.203.0 through 0.20.205.0, 0.23.x before 0.23.2, and 1.0.x before 1.0.2, as used in Cloudera CDH CDH3u0 through CDH3u2, Cloudera hadoop-0.20-sbin before 0.20.2+923.197, and other products, allows remote authenticated users to impersonate arbitrary cluster user accounts via unspecified vectors.