The vgic_distr_mmio_write function in the virtual guest interrupt controller (GIC) distributor (arch/arm/vgic.c) in Xen 4.4.x, when running on an ARM system, allows local guest users to cause a denial of service (NULL pointer dereference and host crash) via unspecified vectors.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.