Xen 3.2.x through 4.4.x does not properly clean memory pages recovered from guests, which allows local guest OS users to obtain sensitive information via unspecified vectors.
http://xenbits.xen.org/xsa/advisory-100.html
http://www.securitytracker.com/id/1030442
http://www.securityfocus.com/bid/68070
http://www.debian.org/security/2014/dsa-3006
http://support.citrix.com/article/CTX140984
http://security.gentoo.org/glsa/glsa-201407-03.xml
http://secunia.com/advisories/60471
http://secunia.com/advisories/60130
http://secunia.com/advisories/60027
http://secunia.com/advisories/59208
http://lists.opensuse.org/opensuse-security-announce/2014-10/msg00003.html
http://lists.opensuse.org/opensuse-security-announce/2014-10/msg00002.html
http://lists.fedoraproject.org/pipermail/package-announce/2014-July/135071.html
http://lists.fedoraproject.org/pipermail/package-announce/2014-July/135068.html