The update_cr8_intercept function in arch/x86/kvm/x86.c in the KVM subsystem in the Linux kernel before 2.6.32-rc1 does not properly handle the absence of an Advanced Programmable Interrupt Controller (APIC), which allows local users to cause a denial of service (NULL pointer dereference and system crash) or possibly gain privileges via a call to the kvm_vcpu_ioctl function.