Ubuntu Security Notice 2691-1 – Andy Lutomirski discovered a flaw in the Linux kernel’s handling of nested NMIs (non-maskable interrupts). An unprivileged local user could exploit this flaw to cause a denial of service (system crash) or potentially escalate their privileges. Colin King discovered a flaw in the add_key function of the Linux kernel’s keyring subsystem. A local user could exploit this flaw to cause a denial of service (memory exhaustion). Various other issues were also addressed.