Xen PV guest before Xen 4.3 checked access permissions to MMIO ranges only after accessing them, allowing host PCI device space memory reads, leading to information disclosure. This is an error in the get_user function. NOTE: the upstream Xen Project considers versions before 4.5.x to be EOL.
Exploitability
AV:LAC:LPR:LUI:NScope
S:CImpact
C:LI:NA:N3.8/CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N