HDFS clients interact with a servlet on the DataNode to browse the HDFS namespace. The NameNode is provided as a query parameter that is not validated in Apache Hadoop before 2.7.0.
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.