{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-72016 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-72016 is a vulnerability in Linux, published on 15 Aug 2026. 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-2026-72016 and fix it if it is affected.\n\nWhat it is: CVE-2026-72016 is a vulnerability in Linux, published on 15 Aug 2026. 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-2026-72016 in the wild and no public exploit code.\n\nAffected product: Linux. 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-2026-72016/ (Markdown: https://insights.sbomify.com/CVE-2026-72016/index.md)","id":"CVE-2026-72016","markdown":"https://insights.sbomify.com/CVE-2026-72016/index.md","name":"CVE-2026-72016","record":{"aliases":["BELL-CVE-2026-72016","DEBIAN-CVE-2026-72016","GHSA-jpp3-3v9r-hwrp","UBUNTU-CVE-2026-72016"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel","requires_auth":"none","summary":"A NULL pointer dereference in the Linux kernel CPU hotplug code can cause a system crash when booting with specific CPU configurations.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncpu/hotplug: Fix NULL kobject warning in cpuhp_smt_enable()\n\nOn arm64, when booting with `maxcpus` greater than the number of present\nCPUs (e.g., QEMU -smp cpus=4,maxcpus=8), some CPUs are marked as 'present'\nbut have not yet been registered via register_cpu(). Consequently,\nthe per-cpu device objects for these CPUs are not yet initialized.\n\nIn cpuhp_smt_enable(), the code iterates over all present CPUs. Calling\n_cpu_up() for these unregistered CPUs eventually leads to\nsysfs_create_group() being called with a NULL kobject (or a kobject\nwithout a directory), triggering the following warning in\nfs/sysfs/group.c:\n\n  WARNING: fs/sysfs/group.c:137 at internal_create_group+0x41c/0x4bc, CPU#2: sh/181\n  [...]\n  Call trace:\n    internal_create_group+0x41c/0x4bc (P)\n    sysfs_create_group+0x18/0x24\n    topology_add_dev+0x1c/0x28\n    cpuhp_invoke_callback+0x104/0x20c\n    __cpuhp_invoke_callback_range+0x94/0x11c\n    _cpu_up+0x200/0x37c\n\nWhen booting with ACPI, arm64 smp_prepare_cpus() currently sets all\nenumerated CPUs as \"present\" regardless of their status in the MADT. This\ncauses issues with SMT hotplug control. For instance, with QEMU's\n\"-smp 4,maxcpus=8\" configuration, the MADT GICC entries are populated as\nfollows:\n\n1. The first four CPUs: `Enabled` set but `Online Capable` not set.\n\n2. The remaining four CPUs: `Online Capable` set but `Enabled` not set\n   to support potential hot-plugging.\n\nFix this by:\n\n1. When booting with ACPI, checking the ACPI_MADT_ENABLED flag in the GICC\n   entry before calling set_cpu_present() during SMP initialization.\n\n2. Properly managing the present mask in acpi_map_cpu() and\n   acpi_unmap_cpu() to support actual CPU hotplug events, This aligns with\n   other architectures like x86 and LoongArch.\n\n3. Update the arm64 CPU hotplug documentation to no longer state that all\n   online-capable vCPUs are marked as present by the kernel at boot time.\n\nThis ensures that only physically available or explicitly enabled CPUs\nare in the present mask, keeping the SMT control logic consistent with\nthe actual hardware state.","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":"cpu/hotplug: Fix NULL kobject warning in cpuhp_smt_enable()","id":"CVE-2026-72016","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"null_dereference","year":"2026"},"n_packages":0,"n_references":3,"next":{"headline":"net: macb: drop in-flight Tx SKBs on close","id":"CVE-2026-72017"},"packages":[],"prev":{"headline":"fs/resctrl: Fix double-add of pseudo-locked region's RMID to free list","id":"CVE-2026-72015"},"products":["Linux"],"published":"2026-08-15","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-08-17","vendors":["Linux"]},"summary":"A NULL pointer dereference in the Linux kernel CPU hotplug code can cause a system crash when booting with specific CPU configurations.","url":"https://insights.sbomify.com/CVE-2026-72016/"}