Vulnerability-Lookup

GHSA-FPJR-J5W9-J6GM

Vulnerability from github – Published: 2026-10-18 18:32 – Updated: 2026-10-18 18:32

Details

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

sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task

ebf1ccff79c4 ("sched_ext: Fix ops.dequeue() semantics") moved the final ops_state store in scx_dispatch_enqueue() after the DSQ unlock so that the custody update and ops.dequeue() precede it. A task can thus be found on a DSQ while still SCX_OPSS_DISPATCHING.

The dequeue and core-sched pick paths wait for the state to clear in ops_dequeue() but the reenqueue paths don't. A reenqueue in that window runs ops.enqueue() and sets SCX_OPSS_QUEUED before the dispatch has completed. The dispatcher's final store then overwrites it with SCX_OPSS_NONE and finish_dispatch() drops every later dispatch of the task.

Wait for SCX_OPSS_DISPATCHING to clear before dequeueing a task for reenqueue, the same way ops_dequeue() does.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-98864"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-18T16:17:40Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task\n\nebf1ccff79c4 (\"sched_ext: Fix ops.dequeue() semantics\") moved the final\nops_state store in scx_dispatch_enqueue() after the DSQ unlock so that the\ncustody update and ops.dequeue() precede it. A task can thus be found on a\nDSQ while still SCX_OPSS_DISPATCHING.\n\nThe dequeue and core-sched pick paths wait for the state to clear in\nops_dequeue() but the reenqueue paths don\u0027t. A reenqueue in that window runs\nops.enqueue() and sets SCX_OPSS_QUEUED before the dispatch has completed.\nThe dispatcher\u0027s final store then overwrites it with SCX_OPSS_NONE and\nfinish_dispatch() drops every later dispatch of the task.\n\nWait for SCX_OPSS_DISPATCHING to clear before dequeueing a task for\nreenqueue, the same way ops_dequeue() does.",
  "id": "GHSA-fpjr-j5w9-j6gm",
  "modified": "2026-10-18T18:32:06Z",
  "published": "2026-10-18T18:32:06Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98864"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/43457bf6550044c40bd6d3fcdf9ea66f5a55d139"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7de9a6fb44eae4f05e68c805d58b9c618815adfa"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-98864 (GCVE-0-2026-98864)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:51 – Updated: 2026-10-18 15:51

Title

sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task

Summary

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task ebf1ccff79c4 ("sched_ext: Fix ops.dequeue() semantics") moved the final ops_state store in scx_dispatch_enqueue() after the DSQ unlock so that the custody update and ops.dequeue() precede it. A task can thus be found on a DSQ while still SCX_OPSS_DISPATCHING. The dequeue and core-sched pick paths wait for the state to clear in ops_dequeue() but the reenqueue paths don't. A reenqueue in that window runs ops.enqueue() and sets SCX_OPSS_QUEUED before the dispatch has completed. The dispatcher's final store then overwrites it with SCX_OPSS_NONE and finish_dispatch() drops every later dispatch of the task. Wait for SCX_OPSS_DISPATCHING to clear before dequeueing a task for reenqueue, the same way ops_dequeue() does.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 7100 records in the last 180 days details

References

2 references

URL	Tags
https://git.kernel.org/stable/c/43457bf6550044c40…
https://git.kernel.org/stable/c/7de9a6fb44eae4f05…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d , < 43457bf6550044c40bd6d3fcdf9ea66f5a55d139 (git) Affected: ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d , < 7de9a6fb44eae4f05e68c805d58b9c618815adfa (git)
Linux	Linux	Affected: 7.1 Unaffected: 0 , < 7.1 (semver) Unaffected: 7.2.10 , ≤ 7.2.* (semver) Unaffected: 7.3-rc5 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext/ext.c",
            "kernel/sched/ext/internal.h",
            "kernel/sched/ext/sub.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "43457bf6550044c40bd6d3fcdf9ea66f5a55d139",
              "status": "affected",
              "version": "ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d",
              "versionType": "git"
            },
            {
              "lessThan": "7de9a6fb44eae4f05e68c805d58b9c618815adfa",
              "status": "affected",
              "version": "ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext/ext.c",
            "kernel/sched/ext/internal.h",
            "kernel/sched/ext/sub.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc5",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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                  "versionEndExcluding": "7.2.10",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc5",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task\n\nebf1ccff79c4 (\"sched_ext: Fix ops.dequeue() semantics\") moved the final\nops_state store in scx_dispatch_enqueue() after the DSQ unlock so that the\ncustody update and ops.dequeue() precede it. A task can thus be found on a\nDSQ while still SCX_OPSS_DISPATCHING.\n\nThe dequeue and core-sched pick paths wait for the state to clear in\nops_dequeue() but the reenqueue paths don\u0027t. A reenqueue in that window runs\nops.enqueue() and sets SCX_OPSS_QUEUED before the dispatch has completed.\nThe dispatcher\u0027s final store then overwrites it with SCX_OPSS_NONE and\nfinish_dispatch() drops every later dispatch of the task.\n\nWait for SCX_OPSS_DISPATCHING to clear before dequeueing a task for\nreenqueue, the same way ops_dequeue() does."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-18T15:51:25.532Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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    "cveId": "CVE-2026-98864",
    "datePublished": "2026-10-18T15:51:25.532Z",
    "dateReserved": "2026-09-25T10:25:14.377Z",
    "dateUpdated": "2026-10-18T15:51:25.532Z",
    "state": "PUBLISHED"
  },
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}

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.

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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.
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