CVE-2026-98463

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Derive SCX_RQ_IN_WAKEUP from the core enqueue flags schedule_deferred_locked() skips scheduling a deferred action while SCX_RQ_IN_WAKEUP is set and relies on the task_woken_scx() call that follows a wakeup enqueue to run it. enqueue_task_scx() sets the flag from the merged enqueue flags, which include the flags stashed for a remote activation. move_remote_task_to_local_dsq() thus sets SCX_RQ_IN_WAKEUP on the destination rq when the moved task was woken up, although no task_woken_scx() follows that activation. An IMMED insert into a busy destination requests a local reenqueue during that enqueue. The request gets linked but not scheduled and stays pending until an unrelated wakeup or preemption on that CPU runs the deferred actions. The IMMED task sits behind the running task in the meantime. If nothing runs them before the scheduler is disabled, the request outlives the scheduler and points into its freed per-cpu area, which the next scheduler dereferences from run_deferred(). Test the core enqueue flags for the wakeup bit. Only the core's wakeup path is followed by task_woken_scx().

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-10-18 16:16:56.770000

Last modified

2026-10-19 10:18:55.960000

View original CVE JSON

{
  "id": "CVE-2026-98463",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-10-18T16:16:56.770",
  "lastModified": "2026-10-19T10:18:55.960",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Derive SCX_RQ_IN_WAKEUP from the core enqueue flags\n\nschedule_deferred_locked() skips scheduling a deferred action while\nSCX_RQ_IN_WAKEUP is set and relies on the task_woken_scx() call that follows\na wakeup enqueue to run it. enqueue_task_scx() sets the flag from the merged\nenqueue flags, which include the flags stashed for a remote activation.\nmove_remote_task_to_local_dsq() thus sets SCX_RQ_IN_WAKEUP on the\ndestination rq when the moved task was woken up, although no\ntask_woken_scx() follows that activation.\n\nAn IMMED insert into a busy destination requests a local reenqueue during\nthat enqueue. The request gets linked but not scheduled and stays pending\nuntil an unrelated wakeup or preemption on that CPU runs the deferred\nactions. The IMMED task sits behind the running task in the meantime. If\nnothing runs them before the scheduler is disabled, the request outlives the\nscheduler and points into its freed per-cpu area, which the next scheduler\ndereferences from run_deferred().\n\nTest the core enqueue flags for the wakeup bit. Only the core's wakeup path\nis followed by task_woken_scx()."
    }
  ],
  "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": "997967adf10ce26c3e7bd89598b3ded62b943052",
              "lessThan": "6c401ae426e20e53a3398a8e79afd0964c0f5110",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "57ccf5ccdc56954f2a91a7f66684fd31c566bde5",
              "lessThan": "3fdf2ceb31e8aff77451e468bc8409e10587916a",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "57ccf5ccdc56954f2a91a7f66684fd31c566bde5",
              "lessThan": "df5cdc2c832ca4e8a6d774596b9005558761a403",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "ee502c056c4c9cce4c132ccb588e06ffe5b831c1",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "6.18.19",
              "lessThan": "6.18.55",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "6.19.9",
              "lessThan": "6.20",
              "versionType": "semver",
              "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": "7.0",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "7.0",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.55",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.9",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/3fdf2ceb31e8aff77451e468bc8409e10587916a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/6c401ae426e20e53a3398a8e79afd0964c0f5110",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/df5cdc2c832ca4e8a6d774596b9005558761a403",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}