FKIE_CVE-2026-89520

Vulnerability from fkie_nvd - Published: 2026-09-11 20:19 - Updated: 2026-10-30 13:20
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: sched/core: Make core-sched flips wait for in-flight selections Core scheduling's pick_next_task() operates on all sibling rqs under one acquisition of the shared core-wide lock. A ->pick_task() that releases the rq lock leaves every sibling __lock momentarily free, letting __sched_core_flip(false) complete mid-selection and rebind rq_lockp() under it. The selection resumes on the split locks, touching sibling state it no longer protects, and __schedule() finally releases a lock that was never taken while leaking the one that was. Count in-flight core-wide selections in the leader's rq->core_pick_in_flight and make __sched_core_flip() wait for the count to drain. The count only changes under the shared lock, which the flip holds while sampling, so no other ordering is needed. The wait can repeat while selections overlap, but the flip backs off between samples and flips are rare cookie-lifetime events. sched_core_cpu_deactivate() moves the count to the new leader - a stale copy left behind would bias it forever if that CPU later returns as its own leader.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/23eda24f325a6e6d686d30ec75f2e9d6745e2015
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3e2511bffa93a639774a99e392181e21d28677e2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8e9376420321026ae1a0d8c3040682242db10be7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9d69422ddaa13526c2223444e237d948d6e44728
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a2a16896ed53046f275f56a6cd8ca3fb6f12c4f3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f3629c63a4af3e491381780bc6c123cb498c4c40
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/core.c",
            "kernel/sched/sched.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "8e9376420321026ae1a0d8c3040682242db10be7",
              "status": "affected",
              "version": "539f65125d20aacab54d02d77f10a839f45b09dc",
              "versionType": "git"
            },
            {
              "lessThan": "a2a16896ed53046f275f56a6cd8ca3fb6f12c4f3",
              "status": "affected",
              "version": "539f65125d20aacab54d02d77f10a839f45b09dc",
              "versionType": "git"
            },
            {
              "lessThan": "3e2511bffa93a639774a99e392181e21d28677e2",
              "status": "affected",
              "version": "539f65125d20aacab54d02d77f10a839f45b09dc",
              "versionType": "git"
            },
            {
              "lessThan": "9d69422ddaa13526c2223444e237d948d6e44728",
              "status": "affected",
              "version": "539f65125d20aacab54d02d77f10a839f45b09dc",
              "versionType": "git"
            },
            {
              "lessThan": "23eda24f325a6e6d686d30ec75f2e9d6745e2015",
              "status": "affected",
              "version": "539f65125d20aacab54d02d77f10a839f45b09dc",
              "versionType": "git"
            },
            {
              "lessThan": "f3629c63a4af3e491381780bc6c123cb498c4c40",
              "status": "affected",
              "version": "539f65125d20aacab54d02d77f10a839f45b09dc",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/core.c",
            "kernel/sched/sched.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.14"
            },
            {
              "lessThan": "5.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "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/core: Make core-sched flips wait for in-flight selections\n\nCore scheduling\u0027s pick_next_task() operates on all sibling rqs under one\nacquisition of the shared core-wide lock. A -\u003epick_task() that releases the\nrq lock leaves every sibling __lock momentarily free, letting\n__sched_core_flip(false) complete mid-selection and rebind rq_lockp() under\nit. The selection resumes on the split locks, touching sibling state it no\nlonger protects, and __schedule() finally releases a lock that was never\ntaken while leaking the one that was.\n\nCount in-flight core-wide selections in the leader\u0027s rq-\u003ecore_pick_in_flight\nand make __sched_core_flip() wait for the count to drain. The count only\nchanges under the shared lock, which the flip holds while sampling, so no\nother ordering is needed. The wait can repeat while selections overlap, but\nthe flip backs off between samples and flips are rare cookie-lifetime\nevents.\n\nsched_core_cpu_deactivate() moves the count to the new leader - a stale copy\nleft behind would bias it forever if that CPU later returns as its own\nleader."
    }
  ],
  "id": "CVE-2026-89520",
  "lastModified": "2026-10-30T13:20:18.220",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-11T20:19:34.647",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/23eda24f325a6e6d686d30ec75f2e9d6745e2015"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3e2511bffa93a639774a99e392181e21d28677e2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8e9376420321026ae1a0d8c3040682242db10be7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9d69422ddaa13526c2223444e237d948d6e44728"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a2a16896ed53046f275f56a6cd8ca3fb6f12c4f3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f3629c63a4af3e491381780bc6c123cb498c4c40"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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