CVE-2019-7221

Public on 2019-02-26
Modified on 2019-03-08
Description
A use-after-free vulnerability was found in the way the Linux kernel's KVM hypervisor emulates a preemption timer for L2 guests when nested (=1) virtualization is enabled. This high resolution timer(hrtimer) runs when a L2 guest is active. After VM exit, the sync_vmcs12() timer object is stopped. The use-after-free occurs if the timer object is freed before calling sync_vmcs12() routine. A guest user/process could use this flaw to crash the host kernel resulting in a denial of service or, potentially, gain privileged access to a system.
Severity
Important
CVSS v3 Base Score
7.5
See breakdown

Affected Packages

Platform Package Release Date Advisory
Amazon Linux 2 kernel 2019-03-07 18:24 ALAS2-2019-1165
Amazon Linux 1 kernel 2019-02-26 18:55 ALAS-2019-1165

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv3 7.5 CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
NVD CVSSv2 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P
NVD CVSSv3 7.8 CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H