Public Date:
769721: CVE-2011-4622 kernel: kvm: pit timer with no irqchip crashes the system

The MITRE CVE dictionary describes this issue as:

The create_pit_timer function in arch/x86/kvm/i8254.c in KVM 83, and possibly other versions, does not properly handle when Programmable Interval Timer (PIT) interrupt requests (IRQs) when a virtual interrupt controller (irqchip) is not available, which allows local users to cause a denial of service (NULL pointer dereference) by starting a timer.

Find out more about CVE-2011-4622 from the MITRE CVE dictionary dictionary and NIST NVD.


This issue did not affect the versions of Linux kernel as shipped with Red Hat Enterprise Linux 4 and Red Hat Enterprise MRG as they did not provide support for the KVM subsystem. It has been addressed in Red Hat Enterprise 5 and 6 via and

CVSS v2 metrics

NOTE: The following CVSS v2 metrics and score provided are preliminary and subject to review.

Base Score 4.9
Base Metrics AV:L/AC:L/Au:N/C:N/I:N/A:C
Access Vector Local
Access Complexity Low
Authentication None
Confidentiality Impact None
Integrity Impact None
Availability Impact Complete

Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).

Red Hat Security Errata

Platform Errata Release Date
Red Hat Enterprise Linux version 6 (kernel) RHSA-2012:0350 2012-03-06
Red Hat Enterprise Linux Virtualization version 5 (kvm) RHSA-2012:0051 2012-01-23

Affected Packages State

Platform Package State
Red Hat Enterprise Linux 5 kvm Affected
Red Hat Enterprise Linux 4 kernel Not affected