Vulnerability-Lookup

CVE-2026-74731 (GCVE-0-2026-74731)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:33 – Updated: 2026-08-22 15:33

Title

sched_ext: Skip sub-disable teardown for never-linked sub-schedulers

Summary

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Skip sub-disable teardown for never-linked sub-schedulers A sub-scheduler enable can fail before scx_link_sched() links the sched into the hierarchy, e.g. when the parent is already being disabled, and cleanup still runs the full scx_sub_disable(). That is racy against root disable: drain_descendants() is the only ordering between a sub's disable-time task walk and root disable's all-task teardown, and an unlinked sub is invisible to it. Root's teardown can thus run between the never-linked sub's drain and its walk, exiting every task to no scheduler. The walk then trips the membership WARN and re-homes the exited tasks onto the dying hierarchy, a use-after-free. Skip the cgroup ownership reset and the task walk if @sch was never linked, indicated by the empty ->sibling as unlinking only happens later in the same function. The membership WARN remains valid: a linked sub is always waited on by an ancestor's drain.

Severity

No CVSS data available.

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/6428093a4a986c38c…
https://git.kernel.org/stable/c/8c13364db9c9a43ed…

Impacted products

2 products

Vendor	Product	Version	CPE status
Linux	Linux	Affected: 337ec00b1d9c676f637651c2cefddb8612b867ee , < 6428093a4a986c38c9089b5eb32b56d914ef437a (git) Affected: 337ec00b1d9c676f637651c2cefddb8612b867ee , < 8c13364db9c9a43ed286f3a8d0fb9477b1adc43c (git)	guessed
Linux	Linux	Affected: 7.1 Unaffected: 0 , < 7.1 (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)	guessed

Show details on NVD website

JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext/ext.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6428093a4a986c38c9089b5eb32b56d914ef437a",
              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "8c13364db9c9a43ed286f3a8d0fb9477b1adc43c",
              "status": "affected",
              "version": "337ec00b1d9c676f637651c2cefddb8612b867ee",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext/ext.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "lessThan": "7.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.9",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Skip sub-disable teardown for never-linked sub-schedulers\n\nA sub-scheduler enable can fail before scx_link_sched() links the sched into\nthe hierarchy, e.g. when the parent is already being disabled, and cleanup\nstill runs the full scx_sub_disable().\n\nThat is racy against root disable: drain_descendants() is the only ordering\nbetween a sub\u0027s disable-time task walk and root disable\u0027s all-task teardown,\nand an unlinked sub is invisible to it. Root\u0027s teardown can thus run between\nthe never-linked sub\u0027s drain and its walk, exiting every task to no\nscheduler.\n\nThe walk then trips the membership WARN and re-homes the exited tasks onto\nthe dying hierarchy, a use-after-free.\n\nSkip the cgroup ownership reset and the task walk if @sch was never linked,\nindicated by the empty -\u003esibling as unlinking only happens later in the same\nfunction. The membership WARN remains valid: a linked sub is always waited\non by an ancestor\u0027s drain."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-22T15:33:20.294Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6428093a4a986c38c9089b5eb32b56d914ef437a"
        },
        {
          "url": "https://git.kernel.org/stable/c/8c13364db9c9a43ed286f3a8d0fb9477b1adc43c"
        }
      ],
      "title": "sched_ext: Skip sub-disable teardown for never-linked sub-schedulers",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74731",
    "datePublished": "2026-08-22T15:33:20.294Z",
    "dateReserved": "2026-08-15T05:44:03.930Z",
    "dateUpdated": "2026-08-22T15:33:20.294Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-74731\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-22T16:16:48.257\",\"lastModified\":\"2026-08-22T16:16:48.257\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nsched_ext: Skip sub-disable teardown for never-linked sub-schedulers\\n\\nA sub-scheduler enable can fail before scx_link_sched() links the sched into\\nthe hierarchy, e.g. when the parent is already being disabled, and cleanup\\nstill runs the full scx_sub_disable().\\n\\nThat is racy against root disable: drain_descendants() is the only ordering\\nbetween a sub\u0027s disable-time task walk and root disable\u0027s all-task teardown,\\nand an unlinked sub is invisible to it. Root\u0027s teardown can thus run between\\nthe never-linked sub\u0027s drain and its walk, exiting every task to no\\nscheduler.\\n\\nThe walk then trips the membership WARN and re-homes the exited tasks onto\\nthe dying hierarchy, a use-after-free.\\n\\nSkip the cgroup ownership reset and the task walk if @sch was never linked,\\nindicated by the empty -\u003esibling as unlinking only happens later in the same\\nfunction. The membership WARN remains valid: a linked sub is always waited\\non by an ancestor\u0027s drain.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"kernel/sched/ext/ext.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"337ec00b1d9c676f637651c2cefddb8612b867ee\",\"lessThan\":\"6428093a4a986c38c9089b5eb32b56d914ef437a\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"337ec00b1d9c676f637651c2cefddb8612b867ee\",\"lessThan\":\"8c13364db9c9a43ed286f3a8d0fb9477b1adc43c\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"kernel/sched/ext/ext.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"7.1\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"7.1\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.9\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/6428093a4a986c38c9089b5eb32b56d914ef437a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/8c13364db9c9a43ed286f3a8d0fb9477b1adc43c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}

FKIE_CVE-2026-74731

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-22 16:16

Severity

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/6428093a4a986c38c9089b5eb32b56d914ef437a
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/8c13364db9c9a43ed286f3a8d0fb9477b1adc43c

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext/ext.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6428093a4a986c38c9089b5eb32b56d914ef437a",
              "status": "affected",
              "version": "337ec00b1d9c676f637651c2cefddb8612b867ee",
              "versionType": "git"
            },
            {
              "lessThan": "8c13364db9c9a43ed286f3a8d0fb9477b1adc43c",
              "status": "affected",
              "version": "337ec00b1d9c676f637651c2cefddb8612b867ee",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext/ext.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "lessThan": "7.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Skip sub-disable teardown for never-linked sub-schedulers\n\nA sub-scheduler enable can fail before scx_link_sched() links the sched into\nthe hierarchy, e.g. when the parent is already being disabled, and cleanup\nstill runs the full scx_sub_disable().\n\nThat is racy against root disable: drain_descendants() is the only ordering\nbetween a sub\u0027s disable-time task walk and root disable\u0027s all-task teardown,\nand an unlinked sub is invisible to it. Root\u0027s teardown can thus run between\nthe never-linked sub\u0027s drain and its walk, exiting every task to no\nscheduler.\n\nThe walk then trips the membership WARN and re-homes the exited tasks onto\nthe dying hierarchy, a use-after-free.\n\nSkip the cgroup ownership reset and the task walk if @sch was never linked,\nindicated by the empty -\u003esibling as unlinking only happens later in the same\nfunction. The membership WARN remains valid: a linked sub is always waited\non by an ancestor\u0027s drain."
    }
  ],
  "id": "CVE-2026-74731",
  "lastModified": "2026-08-22T16:16:48.257",
  "metrics": {},
  "published": "2026-08-22T16:16:48.257",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6428093a4a986c38c9089b5eb32b56d914ef437a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8c13364db9c9a43ed286f3a8d0fb9477b1adc43c"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

GHSA-39HF-RF3C-RJQV

Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-22 18:30

Details

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

sched_ext: Skip sub-disable teardown for never-linked sub-schedulers

A sub-scheduler enable can fail before scx_link_sched() links the sched into the hierarchy, e.g. when the parent is already being disabled, and cleanup still runs the full scx_sub_disable().

That is racy against root disable: drain_descendants() is the only ordering between a sub's disable-time task walk and root disable's all-task teardown, and an unlinked sub is invisible to it. Root's teardown can thus run between the never-linked sub's drain and its walk, exiting every task to no scheduler.

The walk then trips the membership WARN and re-homes the exited tasks onto the dying hierarchy, a use-after-free.

Skip the cgroup ownership reset and the task walk if @sch was never linked, indicated by the empty ->sibling as unlinking only happens later in the same function. The membership WARN remains valid: a linked sub is always waited on by an ancestor's drain.

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-74731"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-22T16:16:48Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Skip sub-disable teardown for never-linked sub-schedulers\n\nA sub-scheduler enable can fail before scx_link_sched() links the sched into\nthe hierarchy, e.g. when the parent is already being disabled, and cleanup\nstill runs the full scx_sub_disable().\n\nThat is racy against root disable: drain_descendants() is the only ordering\nbetween a sub\u0027s disable-time task walk and root disable\u0027s all-task teardown,\nand an unlinked sub is invisible to it. Root\u0027s teardown can thus run between\nthe never-linked sub\u0027s drain and its walk, exiting every task to no\nscheduler.\n\nThe walk then trips the membership WARN and re-homes the exited tasks onto\nthe dying hierarchy, a use-after-free.\n\nSkip the cgroup ownership reset and the task walk if @sch was never linked,\nindicated by the empty -\u003esibling as unlinking only happens later in the same\nfunction. The membership WARN remains valid: a linked sub is always waited\non by an ancestor\u0027s drain.",
  "id": "GHSA-39hf-rf3c-rjqv",
  "modified": "2026-08-22T18:30:30Z",
  "published": "2026-08-22T18:30:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74731"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6428093a4a986c38c9089b5eb32b56d914ef437a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8c13364db9c9a43ed286f3a8d0fb9477b1adc43c"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

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.

Detection rules are retrieved from Rulezet.

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.

Action not permitted

CVE-2026-74731 (GCVE-0-2026-74731)

FKIE_CVE-2026-74731

GHSA-39HF-RF3C-RJQV

Tags

Sightings

Nomenclature