Red Hat Security Advisory 2016-0103-01 – The kernel packages contain the Linux kernel, the core of any Linux operating system. It was found that the x86 ISA is prone to a denial of service attack inside a virtualized environment in the form of an infinite loop in the microcode due to the way delivering of benign exceptions such as #DB is handled. A privileged user inside a guest could use this flaw to create denial of service conditions on the host kernel. A use-after-free flaw was found in the way the Linux kernel’s key management subsystem handled keyring object reference counting in certain error path of the join_session_keyring() function. A local, unprivileged user could use this flaw to escalate their privileges on the system.