Kubernetes kubectl cp path traversal on Windows allows arbitrary file writes

A path traversal vulnerability was discovered in the Kubernetes kubectl client's kubectl cp command on Windows. When copying files from a container, kubectl runs tar inside the container to build a tar archive, transfers it over the network, and unpacks it on the local machine. If the tar binary in the container is malicious, it can execute arbitrary code and emit unexpected output, allowing an attacker who controls container contents to write files to arbitrary paths on the user's local machine when kubectl cp is invoked, limited only by the system permissions of the local user. This issue only affects kubectl clients running on Windows.