Vulnerability-Lookup

GHSA-PX5V-F8QG-W5F8

Vulnerability from github – Published: 2026-10-23 15:31 – Updated: 2026-10-23 15:31

Details

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

cgroup/cpuset: Handle cpu hotplug race in guarantee_active_cpus()

With commit 2125c0034c5d ("cgroup/cpuset: Make cpuset hotplug processing synchronous"), the cpuset hotplug operation becomes synchronous. That commit also removes the code that handles race between cpuset_hotplug_work and cpu hotplug notifier with the assumption that race is now gone. Later commit 7a0aabd9ce69 ("cgroup/cpuset: Always use cpu_active_mask") updates the cpuset code to always use cpu_active_mask instead of cpu_online_mask in some places including guarantee_online_cpus() which is renamed to guarantee_active_cpus() in that commit.

In the case of CPU offline operation, cpu_active_mask is updated first in sched_cpu_deactivate() to remove the offline CPU before cpuset_handle_hotplug() is called to update the effective_cpus of the affected cpusets. The cpu_online_mask is updated after that near the end of the offline operation to remove the offline CPU. As a result, the race comes back and the top cpuset may not have any active CPU leading to NULL pointer dereference during the race window when guarantee_active_cpus() is called after cpu_active_mask is updated to remove the CPU to be torn down but before cpuset_handle_hotplug() is able to properly update the effective_cpus of the top cpuset.

Fix this by adding back the NULL cs check to avoid this problem.

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-99065"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-23T13:17:30Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncgroup/cpuset: Handle cpu hotplug race in guarantee_active_cpus()\n\nWith commit 2125c0034c5d (\"cgroup/cpuset: Make cpuset hotplug processing\nsynchronous\"), the cpuset hotplug operation becomes synchronous. That\ncommit also removes the code that handles race between cpuset_hotplug_work\nand cpu hotplug notifier with the assumption that race is now gone.\nLater commit 7a0aabd9ce69 (\"cgroup/cpuset: Always use cpu_active_mask\")\nupdates the cpuset code to always use cpu_active_mask instead of\ncpu_online_mask in some places including guarantee_online_cpus() which\nis renamed to guarantee_active_cpus() in that commit.\n\nIn the case of CPU offline operation, cpu_active_mask is updated\nfirst in sched_cpu_deactivate() to remove the offline CPU before\ncpuset_handle_hotplug() is called to update the effective_cpus of the\naffected cpusets. The cpu_online_mask is updated after that near the end\nof the offline operation to remove the offline CPU. As a result, the race\ncomes back and the top cpuset may not have any active CPU leading to NULL\npointer dereference during the race window when guarantee_active_cpus()\nis called after cpu_active_mask is updated to remove the CPU to be torn\ndown but before cpuset_handle_hotplug() is able to properly update the\neffective_cpus of the top cpuset.\n\nFix this by adding back the NULL cs check to avoid this problem.",
  "id": "GHSA-px5v-f8qg-w5f8",
  "modified": "2026-10-23T15:31:37Z",
  "published": "2026-10-23T15:31:36Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99065"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/23b1ab15ca91f2cffaf149d9bb0fafeb700c7db2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8d88d3221204fbb1b6dc2c0f2f2181fe49126639"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a21c255159bfe0034740292e10d2e258feeeb10d"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-99065 (GCVE-0-2026-99065)

Vulnerability from cvelistv5 – Published: 2026-10-23 12:23 – Updated: 2026-10-23 12:23

Title

cgroup/cpuset: Handle cpu hotplug race in guarantee_active_cpus()

Summary

In the Linux kernel, the following vulnerability has been resolved: cgroup/cpuset: Handle cpu hotplug race in guarantee_active_cpus() With commit 2125c0034c5d ("cgroup/cpuset: Make cpuset hotplug processing synchronous"), the cpuset hotplug operation becomes synchronous. That commit also removes the code that handles race between cpuset_hotplug_work and cpu hotplug notifier with the assumption that race is now gone. Later commit 7a0aabd9ce69 ("cgroup/cpuset: Always use cpu_active_mask") updates the cpuset code to always use cpu_active_mask instead of cpu_online_mask in some places including guarantee_online_cpus() which is renamed to guarantee_active_cpus() in that commit. In the case of CPU offline operation, cpu_active_mask is updated first in sched_cpu_deactivate() to remove the offline CPU before cpuset_handle_hotplug() is called to update the effective_cpus of the affected cpusets. The cpu_online_mask is updated after that near the end of the offline operation to remove the offline CPU. As a result, the race comes back and the top cpuset may not have any active CPU leading to NULL pointer dereference during the race window when guarantee_active_cpus() is called after cpu_active_mask is updated to remove the CPU to be torn down but before cpuset_handle_hotplug() is able to properly update the effective_cpus of the top cpuset. Fix this by adding back the NULL cs check to avoid this problem.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 7063 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/8d88d3221204fbb1b…
https://git.kernel.org/stable/c/a21c255159bfe0034…
https://git.kernel.org/stable/c/23b1ab15ca91f2cff…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 7a0aabd9ce697fc581ec691b21f748050fbcf004 , < 8d88d3221204fbb1b6dc2c0f2f2181fe49126639 (git) Affected: 7a0aabd9ce697fc581ec691b21f748050fbcf004 , < a21c255159bfe0034740292e10d2e258feeeb10d (git) Affected: 7a0aabd9ce697fc581ec691b21f748050fbcf004 , < 23b1ab15ca91f2cffaf149d9bb0fafeb700c7db2 (git)
Linux	Linux	Affected: 6.16 Unaffected: 0 , < 6.16 (semver) Unaffected: 6.18.57 , ≤ 6.18.* (semver) Unaffected: 7.2.11 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/cgroup/cpuset.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "8d88d3221204fbb1b6dc2c0f2f2181fe49126639",
              "status": "affected",
              "version": "7a0aabd9ce697fc581ec691b21f748050fbcf004",
              "versionType": "git"
            },
            {
              "lessThan": "a21c255159bfe0034740292e10d2e258feeeb10d",
              "status": "affected",
              "version": "7a0aabd9ce697fc581ec691b21f748050fbcf004",
              "versionType": "git"
            },
            {
              "lessThan": "23b1ab15ca91f2cffaf149d9bb0fafeb700c7db2",
              "status": "affected",
              "version": "7a0aabd9ce697fc581ec691b21f748050fbcf004",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/cgroup/cpuset.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.57",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.57",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.11",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncgroup/cpuset: Handle cpu hotplug race in guarantee_active_cpus()\n\nWith commit 2125c0034c5d (\"cgroup/cpuset: Make cpuset hotplug processing\nsynchronous\"), the cpuset hotplug operation becomes synchronous. That\ncommit also removes the code that handles race between cpuset_hotplug_work\nand cpu hotplug notifier with the assumption that race is now gone.\nLater commit 7a0aabd9ce69 (\"cgroup/cpuset: Always use cpu_active_mask\")\nupdates the cpuset code to always use cpu_active_mask instead of\ncpu_online_mask in some places including guarantee_online_cpus() which\nis renamed to guarantee_active_cpus() in that commit.\n\nIn the case of CPU offline operation, cpu_active_mask is updated\nfirst in sched_cpu_deactivate() to remove the offline CPU before\ncpuset_handle_hotplug() is called to update the effective_cpus of the\naffected cpusets. The cpu_online_mask is updated after that near the end\nof the offline operation to remove the offline CPU. As a result, the race\ncomes back and the top cpuset may not have any active CPU leading to NULL\npointer dereference during the race window when guarantee_active_cpus()\nis called after cpu_active_mask is updated to remove the CPU to be torn\ndown but before cpuset_handle_hotplug() is able to properly update the\neffective_cpus of the top cpuset.\n\nFix this by adding back the NULL cs check to avoid this problem."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-23T12:23:08.458Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/8d88d3221204fbb1b6dc2c0f2f2181fe49126639"
        },
        {
          "url": "https://git.kernel.org/stable/c/a21c255159bfe0034740292e10d2e258feeeb10d"
        },
        {
          "url": "https://git.kernel.org/stable/c/23b1ab15ca91f2cffaf149d9bb0fafeb700c7db2"
        }
      ],
      "title": "cgroup/cpuset: Handle cpu hotplug race in guarantee_active_cpus()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-99065",
    "datePublished": "2026-10-23T12:23:08.458Z",
    "dateReserved": "2026-09-25T10:25:14.389Z",
    "dateUpdated": "2026-10-23T12:23:08.458Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

Publication & reservation Sightings KEV catalogs Other timestamps

Loading timeline…

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted