Command and Control
Jenkins versions 2.56 and earlier as well as 2.46.1 LTS and earlier are vulnerable to an unauthenticated remote code execution. An unauthenticated remote code execution vulnerability allowed attackers to transfer a serialized Java
SignedObject object to the Jenkins CLI, that would be deserialized using a new
ObjectInputStream, bypassing the existing blacklist-based protection mechanism. We’re fixing this issue by adding
SignedObject to the blacklist. We’re also backporting the new HTTP CLI protocol from Jenkins 2.54 to LTS 2.46.2, and deprecating the remoting-based (i.e. Java serialization) CLI protocol, disabling it by default.