The shadow-paging feature in Xen through 4.8.x mismanages page references and consequently introduces a race condition, which allows guest OS users to obtain Xen privileges, aka XSA-219.Referenceshttps://security.gentoo.org/glsa/201708-03http://www.debian.org/security/2017/dsa-3969http://www.securityfocus.com/bid/99174https://xenbits.xen.org/xsa/advisory-219.htmlhttps://security.gentoo.org/glsa/201710-17
