How severe is CVE-2009-4031?

CVE-2009-4031 has a CVSS 2.0 base score of 7.8, rated high severity.

Is CVE-2009-4031 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-4031?

CVE-2009-4031 primarily affects Linux Linux Kernel. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-4031?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2009-4031 published?

CVE-2009-4031 was published on 2009-11-29 and last updated on 2026-06-16.

CVE-2009-4031

CVE-2009-4031 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 2.0 base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: High (CVSS 2.0 base score 7.8)
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Linux Linux Kernel
Published: 2009-11-29
Last modified: 2026-06-16

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.

Frequently asked questions

What is CVE-2009-4031?: 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.
How severe is CVE-2009-4031?: CVE-2009-4031 has a CVSS 2.0 base score of 7.8, rated high severity.
Is CVE-2009-4031 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-4031?: CVE-2009-4031 primarily affects Linux Linux Kernel. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-4031?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2009-4031 published?: CVE-2009-4031 was published on 2009-11-29 and last updated on 2026-06-16.

References

Affected products (9)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.32:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.32:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.32:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.32:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.32:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.32:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.32:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.32:rc7:*:*:*:*:*:*

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