Class org.apache.sshd.server.keyprovider.SimpleGeneratorHostKeyProvider in Apache MINA SSHD <= 2.9.1 uses Java deserialization to load a serialized java.security.PrivateKey. The class is one of several implementations that an implementor using Apache MINA SSHD can choose for loading the host keys of an SSH server.
Until version 2.1.0, the code affected by this vulnerability appeared in org.apache.sshd:sshd-core
. Version 2.1.0 contains a commit where the code was moved to the package org.apache.sshd:sshd-common
, which did not exist until version 2.1.0.