An issue was discovered in Xen through 4.11.x allowing x86 PV guest OS users to cause a denial of service (host OS crash) or possibly gain host OS privileges because of an interpretation conflict for a union data structure associated with shadow paging. NOTE: this issue exists because of an incorrect fix for CVE-2017-15595.
lists.opensuse.org/opensuse-security-announce/2019-04/msg00072.html
www.securityfocus.com/bid/106182
lists.debian.org/debian-lts-announce/2019/10/msg00008.html
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UXC6BME7SXJI2ZIATNXCAH7RGPI4UKTT/
www.debian.org/security/2019/dsa-4369
xenbits.xen.org/xsa/advisory-280.html