Use-after-free vulnerability in the FIFO event channel code in Xen 4.4.x allows local guest OS administrators to cause a denial of service (host crash) and possibly execute arbitrary code or obtain sensitive information via an invalid guest frame number.
support.citrix.com/article/CTX216071
www.c7zero.info/stuff/csw2017_ExploringYourSystemDeeper_updated.pdf
www.debian.org/security/2016/dsa-3663
www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
www.securityfocus.com/bid/92863
www.securitytracker.com/id/1036754
xenbits.xen.org/xsa/advisory-188.html
xenbits.xen.org/xsa/xsa188.patch