{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2024-40953", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2024-40953", "idYear": 2024, "status": "PUBLISHED", "publishedAt": "2024-07-12T12:31:56.832Z", "updatedAt": "2026-08-05T11:34:12.855Z", "importedAt": "2026-10-24T01:57:16.009Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin()", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin()\n\nUse {READ,WRITE}_ONCE() to access kvm->last_boosted_vcpu to ensure the\nloads and stores are atomic. In the extremely unlikely scenario the\ncompiler tears the stores, it's theoretically possible for KVM to attempt\nto get a vCPU using an out-of-bounds index, e.g. if the write is split\ninto multiple 8-bit stores, and is paired with a 32-bit load on a VM with\n257 vCPUs:\n\n CPU0 CPU1\n last_boosted_vcpu = 0xff;\n\n (last_boosted_vcpu = 0x100)\n last_boosted_vcpu[15:8] = 0x01;\n i = (last_boosted_vcpu = 0x1ff)\n last_boosted_vcpu[7:0] = 0x00;\n\n vcpu = kvm->vcpu_array[0x1ff];\n\nAs detected by KCSAN:\n\n BUG: KCSAN: data-race in kvm_vcpu_on_spin [kvm] / kvm_vcpu_on_spin [kvm]\n\n write to 0xffffc90025a92344 of 4 bytes by task 4340 on cpu 16:\n kvm_vcpu_on_spin (arch/x86/kvm/../../../virt/kvm/kvm_main.c:4112) kvm\n handle_pause (arch/x86/kvm/vmx/vmx.c:5929) kvm_intel\n vmx_handle_exit (arch/x86/kvm/vmx/vmx.c:?\n\t\t arch/x86/kvm/vmx/vmx.c:6606) kvm_intel\n vcpu_run (arch/x86/kvm/x86.c:11107 arch/x86/kvm/x86.c:11211) kvm\n kvm_arch_vcpu_ioctl_run (arch/x86/kvm/x86.c:?) kvm\n kvm_vcpu_ioctl (arch/x86/kvm/../../../virt/kvm/kvm_main.c:?) kvm\n __se_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:904 fs/ioctl.c:890)\n __x64_sys_ioctl (fs/ioctl.c:890)\n x64_sys_call (arch/x86/entry/syscall_64.c:33)\n do_syscall_64 (arch/x86/entry/common.c:?)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n\n read to 0xffffc90025a92344 of 4 bytes by task 4342 on cpu 4:\n kvm_vcpu_on_spin (arch/x86/kvm/../../../virt/kvm/kvm_main.c:4069) kvm\n handle_pause (arch/x86/kvm/vmx/vmx.c:5929) kvm_intel\n vmx_handle_exit (arch/x86/kvm/vmx/vmx.c:?\n\t\t\tarch/x86/kvm/vmx/vmx.c:6606) kvm_intel\n vcpu_run (arch/x86/kvm/x86.c:11107 arch/x86/kvm/x86.c:11211) kvm\n kvm_arch_vcpu_ioctl_run (arch/x86/kvm/x86.c:?) kvm\n kvm_vcpu_ioctl (arch/x86/kvm/../../../virt/kvm/kvm_main.c:?) kvm\n __se_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:904 fs/ioctl.c:890)\n __x64_sys_ioctl (fs/ioctl.c:890)\n x64_sys_call (arch/x86/entry/syscall_64.c:33)\n do_syscall_64 (arch/x86/entry/common.c:?)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n\n value changed: 0x00000012 -> 0x00000000", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "217ece6129f2d3b4fdd18d9e79be9e43d8d14a42", "status": "affected", "versionType": "git", "lessThan": "11a772d5376aa6d3e2e69b5b5c585f79b60c0e17" }, { "version": "217ece6129f2d3b4fdd18d9e79be9e43d8d14a42", "status": "affected", "versionType": "git", "lessThan": "4c141136a28421b78f34969b25a4fa32e06e2180" }, { "version": "217ece6129f2d3b4fdd18d9e79be9e43d8d14a42", "status": "affected", "versionType": "git", "lessThan": "71fbc3af3dacb26c3aa2f30bb3ab05c44d082c84" }, { "version": "217ece6129f2d3b4fdd18d9e79be9e43d8d14a42", "status": "affected", "versionType": "git", "lessThan": "82bd728a06e55f5b5f93d10ce67f4fe7e689853a" }, { "version": "217ece6129f2d3b4fdd18d9e79be9e43d8d14a42", "status": "affected", "versionType": "git", "lessThan": "92c77807d938145c7c3350c944ef9f39d7f6017c" }, { "version": "217ece6129f2d3b4fdd18d9e79be9e43d8d14a42", "status": "affected", "versionType": "git", "lessThan": "a937ef951bba72f48d2402451419d725d70dba20" }, { "version": "217ece6129f2d3b4fdd18d9e79be9e43d8d14a42", "status": "affected", "versionType": "git", "lessThan": "95c8dd79f3a14df96b3820b35b8399bd91b2be60" }, { "version": "217ece6129f2d3b4fdd18d9e79be9e43d8d14a42", "status": "affected", "versionType": "git", "lessThan": "49f683b41f28918df3e51ddc0d928cb2e934ccdb" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "2.6.39", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "2.6.39" }, { "version": "4.19.323", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "4.19.*" }, { "version": "5.4.285", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.4.*" }, { "version": "5.10.228", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.169", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.96", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.36", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.9.7", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.9.*" }, { "version": "6.10", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }