{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2024-40953 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2024-40953 is a high-severity vulnerability in Linux kernel, published on 12 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2024-40953 and fix it if it is affected.\n\nWhat it is: CVE-2024-40953 is a high-severity vulnerability in Linux kernel, published on 12 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2024-40953 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2024-40953/ (Markdown: https://insights.sbomify.com/CVE-2024-40953/index.md)","id":"CVE-2024-40953","markdown":"https://insights.sbomify.com/CVE-2024-40953/index.md","name":"CVE-2024-40953","record":{"aliases":["BELL-CVE-2024-40953","DEBIAN-CVE-2024-40953","GHSA-j7wr-633c-vhmr","UBUNTU-CVE-2024-40953"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel KVM","requires_auth":"low_privilege","summary":"A data race in KVM's spin handling can cause out-of-bounds memory access, potentially leading to a kernel crash or denial of service.","user_interaction":"not_required","vuln_class":"race_condition"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.9,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H","version":"3.1"},"cwes":[{"id":"CWE-362","name":"Concurrent Execution using Shared Resource with Improper Synchronization"}],"description":"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-\u003elast_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-\u003evcpu_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 -\u003e 0x00000000","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin()","id":"CVE-2024-40953","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"race_condition","year":"2024"},"n_packages":0,"n_references":8,"next":{"headline":"net: do not leave a dangling sk pointer, when socket creation fails","id":"CVE-2024-40954"},"packages":[],"prev":{"headline":"ocfs2: fix NULL pointer dereference in ocfs2_journal_dirty()","id":"CVE-2024-40952"},"products":["Linux"],"published":"2024-07-12","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"A data race in KVM's spin handling can cause out-of-bounds memory access, potentially leading to a kernel crash or denial of service.","url":"https://insights.sbomify.com/CVE-2024-40953/"}