CVE-2016-0728

La función join_session_keyring en security/keys/process_keys.c en el kernel de Linux en versiones anteriores a 4.4.1 no maneja correctamente referencias a objetos en un cierto caso de error, lo que permite a usuarios locales obtener privilegios o provocar una denegación de servicio (desbordamiento de entero y uso después de liberación) a través de comandos keyctl manipulados.

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.

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.