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) MMUEXTMARKSUPER or (2) MMUEXTUNMARKSUPER sub-op in the HYPERVISORmmuextop hypercall or (3) unknown vectors related to page table updates.