CMPXCHG8B emulation in Xen 3.3.x through 4.7.x on x86 systems allows local HVM guest OS users to obtain sensitive information from host stack memory via a "supposedly-ignored" operand size prefix.
http://www.debian.org/security/2017/dsa-3847
http://www.securityfocus.com/bid/94863
http://www.securitytracker.com/id/1037468
http://xenbits.xen.org/xsa/advisory-200.html
Source: MITRE
Published: 2017-01-26
Updated: 2017-11-04
Type: CWE-200
Base Score: 2.1
Vector: AV:L/AC:L/Au:N/C:P/I:N/A:N
Impact Score: 2.9
Exploitability Score: 3.9
Severity: LOW
Base Score: 3.3
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Impact Score: 1.4
Exploitability Score: 1.8
Severity: LOW