Xen 4.4.x, 4.5.x, and 4.6.x does not limit the number of printk console messages when reporting unimplemented hypercalls, which allows local guests to cause a denial of service via a sequence of (1) HYPERVISOR_physdev_op hypercalls, which are not properly handled in the do_physdev_op function in arch/arm/physdev.c, or (2) HYPERVISOR_hvm_op hypercalls, which are not properly handled in the do_hvm_op function in arch/arm/hvm.c.

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.

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.

The p2m_pod_emergency_sweep function in arch/x86/mm/p2m-pod.c in Xen 3.4.x, 3.5.x, and 3.6.x is not preemptible, which allows local x86 HVM guest administrators to cause a denial of service (CPU consumption and possibly reboot) via crafted memory contents that triggers a "time-consuming linear scan," related to Populate-on-Demand.

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.

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.

libxl in Xen 4.1.x through 4.6.x does not properly handle the readonly flag on disks when using the qemu-xen device model, which allows local guest users to write to a read-only disk image.

The xenmem_add_to_physmap_one function in arch/arm/mm.c in Xen 4.5.x, 4.4.x, and earlier does not limit the number of printk console messages when reporting a failure to retrieve a reference on a foreign page, which allows remote domains to cause a denial of service by leveraging permissions to map the memory of a foreign guest.

The C+ mode offload emulation in the RTL8139 network card device model in QEMU, as used in Xen 4.5.x and earlier, allows remote attackers to read process heap memory via unspecified vectors.