| Description: | The load_segment_descriptor implementation in arch/x86/kvm/emulate.c in the Linux kernel before 4.9.5 improperly emulates a "MOV SS, NULL selector" instruction, which allows guest OS users to cause a denial of service (guest OS crash) or gain guest OS privileges via a crafted application. Andy Lutomirski and Willy Tarreau discovered that the KVM implementation in the Linux kernel did not properly emulate instructions on the SS segment register. A local attacker in a guest virtual machine could use this to cause a denial of service (guest OS crash) or possibly gain administrative privileges in the guest OS.
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