In Apache Ignite 2.3 or earlier, the serialization mechanism does not have a list of classes allowed for serialization/deserialization, which makes it possible to run arbitrary code when 3-rd party vulnerable classes are present in Ignite classpath. The vulnerability can be exploited if the one sends a specially prepared form of a serialized object to one of the deserialization endpoints of some Ignite components - discovery SPI, Ignite persistence, Memcached endpoint, socket steamer.