CVE-2009-4031 Denial of service in n/a

High 7.8 Published 27 Nov 2009 Updated 7 Aug 2024

Guest OS users can cause host denial of service via increased scheduling latency by exploiting a flaw in the KVM x86 emulator instruction fetching.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2009-4031?

CVE-2009-4031 is a high-severity denial of service vulnerability in Linux kernel, published on 27 Nov 2009. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

The do_insn_fetch function in arch/x86/kvm/emulate.c in the x86 emulator in the KVM subsystem in the Linux kernel before 2.6.32-rc8-next-20091125 tries to interpret instructions that contain too many bytes to be valid, which allows guest OS users to cause a denial of service (increased scheduling latency) on the host OS via unspecified manipulations related to SMP support.

Weakness: CWE-20

Which versions are affected by CVE-2009-4031?

It affects 1 product.

Linux distribution packages (10)

`kmod-kvm` Red Hat:rhel_virtualization:5::client	All versions	`0:83-105.el5_4.13`
`kvm` Red Hat:rhel_virtualization:5::client	All versions	`0:83-105.el5_4.13`
`kvm-debuginfo` Red Hat:rhel_virtualization:5::client	All versions	`0:83-105.el5_4.13`
`kvm-qemu-img` Red Hat:rhel_virtualization:5::client	All versions	`0:83-105.el5_4.13`
`kvm-tools` Red Hat:rhel_virtualization:5::client	All versions	`0:83-105.el5_4.13`
`kmod-kvm` Red Hat:rhel_virtualization:5::server	All versions	`0:83-105.el5_4.13`
`kvm` Red Hat:rhel_virtualization:5::server	All versions	`0:83-105.el5_4.13`
`kvm-debuginfo` Red Hat:rhel_virtualization:5::server	All versions	`0:83-105.el5_4.13`
`kvm-qemu-img` Red Hat:rhel_virtualization:5::server	All versions	`0:83-105.el5_4.13`
`kvm-tools` Red Hat:rhel_virtualization:5::server	All versions	`0:83-105.el5_4.13`

Products include Linux kernel.

How do I fix CVE-2009-4031?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2009-4031 being exploited?

There is no known exploitation of CVE-2009-4031 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as GHSA-vmf9-49hh-xhh2, RHSA-2009:1659.