Xen 4.4.x, when running on an ARM system, does not properly context switch the CNTKCTL_EL1 register, which allows local guest users to modify the hardware timers and cause a denial of service (crash) via unspecified vectors.Referenceshttp://www.securityfocus.com/bid/67157http://xenbits.xen.org/xsa/advisory-91.htmlhttp://www.openwall.com/lists/oss-security/2014/04/30/5http://www.securitytracker.com/id/1030184http://www.openwall.com/lists/oss-security/2014/04/30/11http://secunia.com/advisories/58347
