4.9 Medium
CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:L/AC:L/Au:N/C:N/I:N/A:C
6.5 Medium
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
0.001 Low
EPSS
Percentile
25.1%
So far, x86 PVH guests can be configured with or without Local APICs. Configurations with Local APICs are identical to x86 HVM guests, and will use as much hardware acceleration support as possible. Configurations without Local APICs try to turn off all hardware acceleration, and disable all software emulation.
Multiple paths in Xen assume the presence of a Local APIC without sufficient checks, and can fall over a NULL pointer. On Intel hardware, the logic to turn off hardware acceleration is incomplete and leaves the guest with full control of the real Task Priority Register.
A malicious or buggy guest may cause a hypervisor crash, resulting in a Denial of Service (DoS) affecting the entire host.
Xen version 4.8 and onwards are vulnerable.
Only x86 systems are vulnerable. ARM systems are not vulnerable.
Only x86 PVH guests can exploit the vulnerability. x86 PV and HVM guests cannot exploit the vulnerability.
4.9 Medium
CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:L/AC:L/Au:N/C:N/I:N/A:C
6.5 Medium
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
0.001 Low
EPSS
Percentile
25.1%