CVE-2026-72016

UNRATEDCVSS · not yet scoredTrending — 5 sources updated this week
—
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No CVSS published and no exploitation signals yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS v2: —Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

cpu/hotplug: Fix NULL kobject warning in cpuhp_smt_enable()

On arm64, when booting with maxcpus greater than the number of present CPUs (e.g., QEMU -smp cpus=4,maxcpus=8), some CPUs are marked as 'present' but have not yet been registered via register_cpu(). Consequently, the per-cpu device objects for these CPUs are not yet initialized.

In cpuhp_smt_enable(), the code iterates over all present CPUs. Calling _cpu_up() for these unregistered CPUs eventually leads to sysfs_create_group() being called with a NULL kobject (or a kobject without a directory), triggering the following warning in fs/sysfs/group.c:

WARNING: fs/sysfs/group.c:137 at internal_create_group+0x41c/0x4bc, CPU#2: sh/181 [...] Call trace: internal_create_group+0x41c/0x4bc (P) sysfs_create_group+0x18/0x24 topology_add_dev+0x1c/0x28 cpuhp_invoke_callback+0x104/0x20c __cpuhp_invoke_callback_range+0x94/0x11c _cpu_up+0x200/0x37c

When booting with ACPI, arm64 smp_prepare_cpus() currently sets all enumerated CPUs as "present" regardless of their status in the MADT. This causes issues with SMT hotplug control. For instance, with QEMU's "-smp 4,maxcpus=8" configuration, the MADT GICC entries are populated as follows:

  • The first four CPUs: Enabled set but Online Capable not set.
  • The remaining four CPUs: Online Capable set but Enabled not set
to support potential hot-plugging.

Fix this by:

  • When booting with ACPI, checking the ACPI_MADT_ENABLED flag in the GICC
entry before calling set_cpu_present() during SMP initialization.
  • Properly managing the present mask in acpi_map_cpu() and
acpi_unmap_cpu() to support actual CPU hotplug events, This aligns with other architectures like x86 and LoongArch.
  • Update the arm64 CPU hotplug documentation to no longer state that all
online-capable vCPUs are marked as present by the kernel at boot time.

This ensures that only physically available or explicitly enabled CPUs are in the present mask, keeping the SMT control logic consistent with the actual hardware state.

CVSS v3
—
EchelonGraph score
Not yet assessedNo source has published severity data for this CVE yet — no CVSS score from NVD or a CNA, no GitHub advisory, and it is not in CISA KEV. This is not a rating of zero; we cannot assess it yet.
EG Score
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EG Risk
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EPSS PROB
0%
EPSS %ILE
10%
KEV
Not listed

Published

August 15, 2026

Last Modified

August 17, 2026

References (3)

Vendor Advisories for CVE-2026-72016(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 18× in last 7d / 18× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-20 22:56 UTCEPSS rescore
  2. 2026-08-20 03:20 UTCGHSA enrichment
  3. 2026-08-19 17:04 UTCEPSS rescore
  4. 2026-08-18 13:49 UTCEPSS rescore
  5. 2026-08-18 13:49 UTCEPSS rescore
  6. 2026-08-17 13:47 UTCEPSS rescore
  7. 2026-08-17 06:30 UTCGHSA enrichment
  8. 2026-08-17 06:18 UTCNVD update
  9. 2026-08-17 05:34 UTCEG score recompute
  10. 2026-08-17 05:34 UTCGHSA enrichment
  11. 2026-08-17 05:25 UTCMITRE cvelistV5
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-16 14:56 UTCEPSS rescore
  14. 2026-08-16 02:15 UTCEPSS rescore
  15. 2026-08-15 06:46 UTCGHSA enrichment
  16. 2026-08-15 06:23 UTCNVD update
  17. 2026-08-15 06:19 UTCEG score recompute
  18. 2026-08-15 06:02 UTCMITRE cvelistV5first tracked

Frequently asked(4)

What is CVE-2026-72016?
CVE-2026-72016 is a publicly disclosed vulnerability published on August 15, 2026. In the Linux kernel, the following vulnerability has been resolved: cpu/hotplug: Fix NULL kobject warning in cpuhpsmtenable() On arm64, when booting with maxcpus greater than the number of present CPUs (e.g., QEMU -smp cpus=4,maxcpus=8), some CPUs are marked as 'present' but have not yet been…
When was CVE-2026-72016 disclosed?
CVE-2026-72016 was first published in the National Vulnerability Database on August 15, 2026, with the most recent update on August 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-72016 actively exploited?
CVE-2026-72016 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 90.1% of all scored CVEs.
How do I remediate CVE-2026-72016?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-72016, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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