Buffer overflow in hw/pt-msi.c in Xen 4.6.x and earlier, when using the qemu-xen-traditional (aka qemu-dm) device model, allows local x86 HVM guest administrators to gain privileges by leveraging a system with access to a passed-through MSI-X capable physical PCI device and MSI-X table entries, related to a "write path."

The fpu_fxrstor function in arch/x86/i387.c in Xen 4.x does not properly handle writes to the hardware FSW.ES bit when running on AMD64 processors, which allows local guest OS users to obtain sensitive register content information from another guest by leveraging pending exception and mask bits. NOTE: this vulnerability exists because of an incorrect fix for CVE-2013-2076.

Xen 4.6.x, 4.5.x, 4.4.x, 4.3.x, and earlier do not initialize x86 FPU stack and XMM registers when XSAVE/XRSTOR are not used to manage guest extended register state, which allows local guest domains to obtain sensitive information from other domains via unspecified vectors.

VMX in Xen 4.6.x and earlier, when using an Intel or Cyrix CPU, allows local HVM guest users to cause a denial of service (guest crash) via vectors related to a non-canonical RIP.

Xen 4.6.x and earlier allows local guest administrators to cause a denial of service (host reboot) via vectors related to multiple mappings of MMIO pages with different cachability settings.

The paging_invlpg function in include/asm-x86/paging.h in Xen 3.3.x through 4.6.x, when using shadow mode paging or nested virtualization is enabled, allows local HVM guest users to cause a denial of service (host crash) via a non-canonical guest address in an INVVPID instruction, which triggers a hypervisor bug check.

The PV superpage functionality in arch/x86/mm.c in Xen 3.4.0, 3.4.1, and 4.1.x through 4.6.x allows local PV guests to obtain sensitive information, cause a denial of service, gain privileges, or have unspecified other impact via a crafted page identifier (MFN) to the (1) MMUEXT_MARK_SUPER or (2) MMUEXT_UNMARK_SUPER sub-op in the HYPERVISOR_mmuext_op hypercall or (3) unknown vectors related to page table updates.

The hvm_set_callback_via function in arch/x86/hvm/irq.c in Xen 4.6 does not limit the number of printk console messages when logging the new callback method, which allows local HVM guest OS users to cause a denial of service via a large number of changes to the callback method (HVM_PARAM_CALLBACK_IRQ).

The libxl toolstack library in Xen 4.1.x through 4.6.x does not properly release mappings of files used as kernels and initial ramdisks when managing multiple domains in the same process, which allows attackers to cause a denial of service (memory and disk consumption) by starting domains.

The memory_exchange function in common/memory.c in Xen 3.2.x through 4.6.x does not properly release locks, which might allow guest OS administrators to cause a denial of service (deadlock or host crash) via unspecified vectors, related to XENMEM_exchange error handling.

The memory_exchange function in common/memory.c in Xen 3.2.x through 4.6.x does not properly hand back pages to a domain, which might allow guest OS administrators to cause a denial of service (host crash) via unspecified vectors related to domain teardown.

Xen 4.6.x and earlier does not properly enforce limits on page order inputs for the (1) XENMEM_increase_reservation, (2) XENMEM_populate_physmap, (3) XENMEM_exchange, and possibly other HYPERVISOR_memory_op suboperations, which allows ARM guest OS administrators to cause a denial of service (CPU consumption, guest reboot, or watchdog timeout and host reboot) and possibly have unspecified other impact via unknown vectors.

The hypercall_create_continuation function in arch/arm/domain.c in Xen 4.4.x through 4.6.x allows local guest users to cause a denial of service (host crash) via a preemptible hypercall to the multicall interface.

The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a denial of service (host OS panic or hang) by triggering many #DB (aka Debug) exceptions, related to svm.c.

The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a denial of service (host OS panic or hang) by triggering many #AC (aka Alignment Check) exceptions, related to svm.c and vmx.c.

The (1) libxl_set_memory_target function in tools/libxl/libxl.c and (2) libxl__build_post function in tools/libxl/libxl_dom.c in Xen 3.4.x through 4.6.x do not properly calculate the balloon size when using the populate-on-demand (PoD) system, which allows local HVM guest users to cause a denial of service (guest crash) via unspecified vectors related to "heavy memory pressure."

Xen 3.2.x through 4.6.x does not limit the number of printk console messages when logging certain pmu and profiling hypercalls, which allows local guests to cause a denial of service via a sequence of crafted (1) HYPERCALL_xenoprof_op hypercalls, which are not properly handled in the do_xenoprof_op function in common/xenoprof.c, or (2) HYPERVISOR_xenpmu_op hypercalls, which are not properly handled in the do_xenpmu_op function in arch/x86/cpu/vpmu.c.

Multiple memory leaks in Xen 4.0 through 4.6.x allow local guest administrators or domains with certain permission to cause a denial of service (memory consumption) via a large number of "teardowns" of domains with the vcpu pointer array allocated using the (1) XEN_DOMCTL_max_vcpus hypercall or the xenoprofile state vcpu pointer array allocated using the (2) XENOPROF_get_buffer or (3) XENOPROF_set_passive hypercall.

The mod_l2_entry function in arch/x86/mm.c in Xen 3.4 through 4.6.x does not properly validate level 2 page table entries, which allows local PV guest administrators to gain privileges via a crafted superpage mapping.

Race condition in the relinquish_memory function in arch/arm/domain.c in Xen 4.6.x and earlier allows local domains with partial management control to cause a denial of service (host crash) via vectors involving the destruction of a domain and using XENMEM_decrease_reservation to reduce the memory of the domain.