CVE-2024-40953

Aliases:UBUNTU-CVE-2024-40953DEBIAN-CVE-2024-40953
Advisory lineage Upstream: 0 Downstream: 48
Modified
Published: 12 Jul 2024, 12:31
Last modified:05 Aug 2026, 11:34

Vulnerability Summary

Overall Risk (default)
medium
32/100
CVSS Score
7.9 HIGH
v3.1 (cve.org)
EPSS Score
0.2% LOW
0% probability +0.19%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

12 Jul 2024, 12:31
Published
Vulnerability first disclosed
05 Aug 2026, 11:34
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin() Use {READ,WRITE}_ONCE() to access kvm->last_boosted_vcpu to ensure the loads and stores are atomic. In the extremely unlikely scenario the compiler tears the stores, it's theoretically possible for KVM to attempt to get a vCPU using an out-of-bounds index, e.g. if the write is split into multiple 8-bit stores, and is paired with a 32-bit load on a VM with 257 vCPUs: CPU0 CPU1 last_boosted_vcpu = 0xff; (last_boosted_vcpu = 0x100) last_boosted_vcpu[15:8] = 0x01; i = (last_boosted_vcpu = 0x1ff) last_boosted_vcpu[7:0] = 0x00; vcpu = kvm->vcpu_array[0x1ff]; As detected by KCSAN: BUG: KCSAN: data-race in kvm_vcpu_on_spin [kvm] / kvm_vcpu_on_spin [kvm] write to 0xffffc90025a92344 of 4 bytes by task 4340 on cpu 16: kvm_vcpu_on_spin (arch/x86/kvm/../../../virt/kvm/kvm_main.c:4112) kvm handle_pause (arch/x86/kvm/vmx/vmx.c:5929) kvm_intel vmx_handle_exit (arch/x86/kvm/vmx/vmx.c:? arch/x86/kvm/vmx/vmx.c:6606) kvm_intel vcpu_run (arch/x86/kvm/x86.c:11107 arch/x86/kvm/x86.c:11211) kvm kvm_arch_vcpu_ioctl_run (arch/x86/kvm/x86.c:?) kvm kvm_vcpu_ioctl (arch/x86/kvm/../../../virt/kvm/kvm_main.c:?) kvm __se_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:904 fs/ioctl.c:890) __x64_sys_ioctl (fs/ioctl.c:890) x64_sys_call (arch/x86/entry/syscall_64.c:33) do_syscall_64 (arch/x86/entry/common.c:?) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) read to 0xffffc90025a92344 of 4 bytes by task 4342 on cpu 4: kvm_vcpu_on_spin (arch/x86/kvm/../../../virt/kvm/kvm_main.c:4069) kvm handle_pause (arch/x86/kvm/vmx/vmx.c:5929) kvm_intel vmx_handle_exit (arch/x86/kvm/vmx/vmx.c:? arch/x86/kvm/vmx/vmx.c:6606) kvm_intel vcpu_run (arch/x86/kvm/x86.c:11107 arch/x86/kvm/x86.c:11211) kvm kvm_arch_vcpu_ioctl_run (arch/x86/kvm/x86.c:?) kvm kvm_vcpu_ioctl (arch/x86/kvm/../../../virt/kvm/kvm_main.c:?) kvm __se_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:904 fs/ioctl.c:890) __x64_sys_ioctl (fs/ioctl.c:890) x64_sys_call (arch/x86/entry/syscall_64.c:33) do_syscall_64 (arch/x86/entry/common.c:?) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) value changed: 0x00000012 -> 0x00000000

CVSS Metrics

  • v3.1•MEDIUM•Score: 4.7CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
  • v3.1•HIGH•Score: 7.9CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H

EPSS Trends

Current EPSS score: 0.20%• Percentile: 10%

Techniques & Countermeasures

  • CWE-362•Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

    The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

Affected Systems

  • debian•linux

    < 5.10.234-1 | < 6.1.99-1 | < 6.9.7-1 | < 6.9.7-1

  • debian•linux-6.1

    < 6.1.119-1~deb11u1

  • ubuntu•linux

    all | < 5.4.0-208.228 | < 5.15.0-133.144 | < 6.8.0-44.44

  • ubuntu•linux-allwinner-5.19

    all

  • ubuntu•linux-aws

    all | < 5.4.0-1140.150 | < 5.15.0-1078.85 | < 6.8.0-1015.16

  • ubuntu•linux-aws-5.0

    all

  • ubuntu•linux-aws-5.11

    all

  • ubuntu•linux-aws-5.13

    all

  • ubuntu•linux-aws-5.15

    < 5.15.0-1080.87~20.04.1

  • ubuntu•linux-aws-5.19

    all

  • ubuntu•linux-aws-5.3

    all

  • ubuntu•linux-aws-5.4

    < 5.4.0-1142.152~18.04.1

  • ubuntu•linux-aws-5.8

    all

  • ubuntu•linux-aws-6.2

    all

  • ubuntu•linux-aws-6.5

    all

  • ubuntu•linux-aws-6.8

    < 6.8.0-1015.16~22.04.1

  • ubuntu•linux-aws-fips

    all | < 5.4.0-1140.151+fips1 | < 5.15.0-1078.85+fips1

  • ubuntu•linux-aws-hwe

    all

  • ubuntu•linux-azure

    all | all | < 5.4.0-1145.152 | < 5.15.0-1081.90 | < 6.8.0-1014.16

  • ubuntu•linux-azure-4.15

    all

  • ubuntu•linux-azure-5.11

    all

  • ubuntu•linux-azure-5.13

    all

  • ubuntu•linux-azure-5.15

    < 5.15.0-1081.90~20.04.1

  • ubuntu•linux-azure-5.19

    all

  • ubuntu•linux-azure-5.3

    all

  • ubuntu•linux-azure-5.4

    < 5.4.0-1145.152~18.04.1

  • ubuntu•linux-azure-5.8

    all

  • ubuntu•linux-azure-6.2

    all

  • ubuntu•linux-azure-6.5

    all

  • ubuntu•linux-azure-6.8

    < 6.8.0-1014.16~22.04.1

  • ubuntu•linux-azure-edge

    all

  • ubuntu•linux-azure-fde

    all | < 5.15.0-1081.90.1

  • ubuntu•linux-azure-fde-5.19

    all

  • ubuntu•linux-azure-fde-6.2

    all

  • ubuntu•linux-azure-fips

    all | < 5.4.0-1145.152+fips1 | < 5.15.0-1080.89+fips1

  • ubuntu•linux-bluefield

    all | < 5.4.0-1099.106 | < 5.15.0-1060.62

  • ubuntu•linux-fips

    all | < 5.4.0-1116.126 | < 5.15.0-133.144+fips1 | < 6.8.0-78.78+fips1

  • ubuntu•linux-gcp

    all | all | < 5.4.0-1143.152 | < 5.15.0-1077.86 | < 6.8.0-1014.16

  • ubuntu•linux-gcp-4.15

    all

  • ubuntu•linux-gcp-5.11

    all

  • ubuntu•linux-gcp-5.13

    all

  • ubuntu•linux-gcp-5.15

    < 5.15.0-1077.86~20.04.1

  • ubuntu•linux-gcp-5.19

    all

  • ubuntu•linux-gcp-5.3

    all

  • ubuntu•linux-gcp-5.4

    < 5.4.0-1143.152~18.04.1

  • ubuntu•linux-gcp-5.8

    all

  • ubuntu•linux-gcp-6.2

    all

  • ubuntu•linux-gcp-6.5

    all

  • ubuntu•linux-gcp-6.8

    < 6.8.0-1014.16~22.04.1

  • ubuntu•linux-gcp-fips

    all | < 5.4.0-1143.152+fips1 | < 5.15.0-1077.86+fips1

Showing first 50 affected entries in server-rendered view.

References (46)