Answer in brief
CVE-2024-40953 records a High severity (CVSS 7.9) vulnerability in KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 <11a772d5376aa6d3e2e69b5b5c585f79b60c0e17 || >=217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 <4c141136a28421b78f34969b25a4fa32e06e2180 || >=217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 <71fbc3af3dacb26c3aa2f30bb3ab05c44d082c84 || >=217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 <82bd728a06e55f5b5f93d10ce67f4fe7e689853a || >=217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 <92c77807d938145c7c3350c944ef9f39d7f6017c || >=217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 <a937ef951bba72f48d2402451419d725d70dba20 || >=217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 <95c8dd79f3a14df96b3820b35b8399bd91b2be60 || >=217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 <49f683b41f28918df3e51ddc0d928cb2e934ccdb | 11a772d5376aa6d3e2e69b5b5c585f79b60c0e17, 4c141136a28421b78f34969b25a4fa32e06e2180, 71fbc3af3dacb26c3aa2f30bb3ab05c44d082c84, 82bd728a06e55f5b5f93d10ce67f4fe7e689853a, 92c77807d938145c7c3350c944ef9f39d7f6017c, a937ef951bba72f48d2402451419d725d70dba20, 95c8dd79f3a14df96b3820b35b8399bd91b2be60, 49f683b41f28918df3e51ddc0d928cb2e934ccdb |
| Linux/Linuxgeneric | 2.6.39 | Not reported |
Published upstream
Jul 12, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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
Quoted source text, attributed separately from HOL analysis.