Description: | The KVM subsystem in the Linux kernel before 3.6.9, when running on hosts that use qemu userspace without XSAVE, allows local users to cause a denial of service (kernel OOPS) by using the KVM_SET_SREGS ioctl to set the X86_CR4_OSXSAVE bit in the guest cr4 register, then calling the KVM_RUN ioctl. Jon Howell reported a flaw in the Linux kernel's KVM (Kernel-based virtual machine) subsystem's handling of the XSAVE feature. On hosts, using qemu userspace, without the XSAVE feature an unprivileged local attacker could exploit this flaw to crash the system.
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