CVE-2024-40953

MEDIUM EPSS 8.9%
Published Jul 12, 20241y ago · Modified Jun 17, 20261w ago
4.7 CVSS 3.1
Medium
Find Similar
Published Jul 12, 2024 1y ago
Last Modified Jun 17, 2026 1w ago

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 Details

Base Score
4.7
Exploitability
1.0
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity High
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
8.9% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-362

Affected Products 11

VendorProductVersionRange
linuxlinux_kernel*≥2.6.39  –  <4.19.323
linuxlinux_kernel*≥4.20  –  <5.4.285
linuxlinux_kernel*≥5.5  –  <5.10.228
linuxlinux_kernel*≥5.11  –  <5.15.169
linuxlinux_kernel*≥5.16  –  <6.1.96
linuxlinux_kernel*≥6.2  –  <6.6.36
linuxlinux_kernel*≥6.7  –  <6.9.7
linuxlinux_kernel6.10any
linuxlinux_kernel6.10any
linuxlinux_kernel6.10any
linuxlinux_kernel6.10any

References 10

  • git.kernel.org https://git.kernel.org/stable/c/11a772d5376aa6d3e2e69b5b5c585f79b60c0e17
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/49f683b41f28918df3e51ddc0d928cb2e934ccdb
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4c141136a28421b78f34969b25a4fa32e06e2180
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/71fbc3af3dacb26c3aa2f30bb3ab05c44d082c84
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/82bd728a06e55f5b5f93d10ce67f4fe7e689853a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/92c77807d938145c7c3350c944ef9f39d7f6017c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/95c8dd79f3a14df96b3820b35b8399bd91b2be60
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/a937ef951bba72f48d2402451419d725d70dba20
    Patch
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/11a772d5376aa6d3e2e69b5b5c585f79b60c0e17
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/49f683b41f28918df3e51ddc0d928cb2e934ccdb
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4c141136a28421b78f34969b25a4fa32e06e2180
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/71fbc3af3dacb26c3aa2f30bb3ab05c44d082c84
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/82bd728a06e55f5b5f93d10ce67f4fe7e689853a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/92c77807d938145c7c3350c944ef9f39d7f6017c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/95c8dd79f3a14df96b3820b35b8399bd91b2be60
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/a937ef951bba72f48d2402451419d725d70dba20
    Patch