Missing Authentication for Critical Function
In Apache Spark through 2.4.5 and 3.0.0-preview through 3.0.0-preview2, a standalone resource manager's master may be configured to require authentication (spark.authenticate) via a shared secret. When enabled, however, a specially-crafted RPC to the master can succeed in starting an application's resources on the Spark cluster, even without the shared key. This can be leveraged to execute shell commands on the host machine. This does not affect Spark clusters using other resource managers (YARN, Mesos, etc).
CWE-306 - Missing Authentication for Critical Function
The software does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.