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 YARN NodeManager daemon in Apache Hadoop 0.23.0 through 0.23.11 and 2.x before 2.5.2, when using Kerberos authentication, allows remote cluster users to change the permissions of certain files to world-readable via a symlink attack in a public tar archive, which is not properly handled during localization, related to distributed cache.

The RPC protocol implementation in Apache Hadoop 2.x before 2.0.6-alpha, 0.23.x before 0.23.9, and 1.x before 1.2.1, when the Kerberos security features are enabled, allows man-in-the-middle attackers to disable bidirectional authentication and obtain sensitive information by forcing a downgrade to simple authentication.

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.