A vulnerability was recently discovered in the rpc.mountd daemon in the nfs-utils package for Linux, that allows a NFSv3 client to escalate the privileges assigned to it in the /etc/exports file at mount time. In particular, it allows the client to access any subdirectory or subtree of an exported directory, regardless of the set file permissions, and regardless of any 'root_squash' or 'all_squash' attributes that would normally be expected to apply to that client.

Certain NFS servers allow users to use mknod to gain privileges by creating a writable kmem device and setting the UID to 0.

Debian's cpio contains a path traversal vulnerability. This issue was introduced by reverting CVE-2015-1197 patches which had caused a regression in --no-absolute-filenames. Upstream has since provided a proper fix to --no-absolute-filenames.

A path traversal vulnerability was found in the CPIO utility. This issue could allow a remote unauthenticated attacker to trick a user into opening a specially crafted archive. During the extraction process, the archiver could follow symlinks outside of the intended directory, which allows files to be written in arbitrary directories through symlinks.