Integer overflow in the x86 shadow pagetable code in Xen allows local guest OS users to cause a denial of service (host crash) or possibly gain privileges by shadowing a superpage mapping.
http://xenbits.xen.org/xsa/advisory-173.html
http://www.securitytracker.com/id/1035587
http://www.securityfocus.com/bid/86318
http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
http://www.debian.org/security/2016/dsa-3554
http://support.citrix.com/article/CTX209443
http://lists.fedoraproject.org/pipermail/package-announce/2016-May/184209.html
http://lists.fedoraproject.org/pipermail/package-announce/2016-May/183350.html
http://lists.fedoraproject.org/pipermail/package-announce/2016-April/183275.html