The do_insn_fetch function in arch/x86/kvm/emulate.c in the x86 emulator in the KVM…
Priority MEDIUM 40CWE-20Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- — Not recorded in CVSS 2.0
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · Complete
- Fix status
- Fixed
Attack profile from CVSS 2.0 · NVD. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
EPSS 0.03112 87th percentileScored 2026-11-07
Fix Fixed Red Hat: 2 advisories
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 9
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | before 2.6.32 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:2.6.32:-:*:*:*:*:*:* | 2.6.32 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:2.6.32:rc1:*:*:*:*:*:* | 2.6.32 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:2.6.32:rc2:*:*:*:*:*:* | 2.6.32 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:2.6.32:rc3:*:*:*:*:*:* | 2.6.32 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:2.6.32:rc4:*:*:*:*:*:* | 2.6.32 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:2.6.32:rc5:*:*:*:*:*:* | 2.6.32 rc5 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:2.6.32:rc6:*:*:*:*:*:* | 2.6.32 rc6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:2.6.32:rc7:*:*:*:*:*:* | 2.6.32 rc7 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions before 2.6.32 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:2.6.32:-:*:*:*:*:*:* Versions 2.6.32 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:2.6.32:rc1:*:*:*:*:*:* Versions 2.6.32 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:2.6.32:rc2:*:*:*:*:*:* Versions 2.6.32 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:2.6.32:rc3:*:*:*:*:*:* Versions 2.6.32 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:2.6.32:rc4:*:*:*:*:*:* Versions 2.6.32 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:2.6.32:rc5:*:*:*:*:*:* Versions 2.6.32 rc5 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:2.6.32:rc6:*:*:*:*:*:* Versions 2.6.32 rc6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:2.6.32:rc7:*:*:*:*:*:* Versions 2.6.32 rc7 Vulnerable ·Linux
Remediation
Red Hat 2 advisories
- RHSA-2009:1692 Released 2009-12-23 · Red Hat rating Importantrhev-hypervisor security and bug fix update
- Red Hat Enterprise Virtualization Hypervisor 5 rhev-hypervisor-5.4-2.1.3.el5_4rhev2_1, rhev-hypervisor-pxe-5.4-2.1.3.el5_4rhev2_1
- RHSA-2009:1659 Released 2009-12-09 · Red Hat rating Moderatekvm security and bug fix update
- Red Hat Enterprise Linux Desktop Multi OS (v. 5 client) kmod-kvm-83-105.el5_4.13, kvm-83-105.el5_4.13, kvm-qemu-img-83-105.el5_4.13 +1
- Red Hat Enterprise Linux Virtualization (v. 5 server) kmod-kvm-83-105.el5_4.13, kvm-83-105.el5_4.13, kvm-qemu-img-83-105.el5_4.13 +1
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux Desktop Multi OS (v. 5 client) | Fixed | RHSA-2009:1659 |
| Red Hat Enterprise Linux Virtualization (v. 5 server) | Fixed | RHSA-2009:1659 |
| Red Hat Enterprise Virtualization Hypervisor 5 | Fixed | RHSA-2009:1692 |
Timeline
- 2026-10-02 Threatist record created from CVE-2009-4031
- 2026-10-03 Alias added: GHSA-vmf9-49hh-xhh2
References
Advisory 6
- [oss-security] 20091125 Re: CVE request: kernel: KVM: x86 emulator: limit instructions to 15 bytes
- SUSE-SA:2010:018
- oval:org.mitre.oval:def:11089
- [oss-security] 20091125 CVE request: kernel: KVM: x86 emulator: limit instructions to 15 bytes
- FEDORA-2009-13098
- https://bugzilla.redhat.com/show_bug.cgi?id=541160
More Linux Kernel vulnerabilities
- TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2009-4031 · CVE Program
- CVE-2009-4031 · NVD
- FIRST EPSS
- GHSA-vmf9-49hh-xhh2 · GitHub Advisory Database · CC BY 4.0
- CVE-2009-4031 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences