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CVE-2024-49573 (GCVE-0-2024-49573)

Vulnerability from cvelistv5 – Published: 2025-01-11 12:35 – Updated: 2026-08-05 11:40
VLAI
Title
sched/fair: Fix NEXT_BUDDY
Summary
In the Linux kernel, the following vulnerability has been resolved: sched/fair: Fix NEXT_BUDDY Adam reports that enabling NEXT_BUDDY insta triggers a WARN in pick_next_entity(). Moving clear_buddies() up before the delayed dequeue bits ensures no ->next buddy becomes delayed. Further ensure no new ->next buddy ever starts as delayed.
Severity
7 (High)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 152e11f6df293e816a6a37c69757033cdc72667d , < 5dbe6816c49197677a5ecce749bd99929da147da (git)
Affected: 152e11f6df293e816a6a37c69757033cdc72667d , < 493afbd187c4c9cc1642792c0d9ba400c3d6d90d (git)
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Linux Linux Affected: 6.12
Unaffected: 0 , < 6.12 (semver)
Unaffected: 6.12.7 , ≤ 6.12.* (semver)
Unaffected: 6.13 , ≤ * (original_commit_for_fix)
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Show details on NVD website
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/fair.c"
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          "versions": [
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              "version": "152e11f6df293e816a6a37c69757033cdc72667d",
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              "version": "0",
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              "versionType": "semver"
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            "baseSeverity": "HIGH",
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              "value": "AV:L - The defect is in the CFS scheduler core (kernel/sched/fair.c), reached by ordinary task wakeup, sleep and load-balancer migration on the local machine. There is no remote or adjacent-network input involved, so an attacker must be able to run code on the system.\nAC:H - The entire bug is gated on the NEXT_BUDDY scheduler feature, which is `SCHED_FEAT(NEXT_BUDDY, false)` \u2014 disabled by default and settable only by root writing /sys/kernel/debug/sched/features on a CONFIG_SCHED_DEBUG=y kernel (sched_feat_write is the sole caller of sched_feat_set; there is no cmdline or sysctl path). An unprivileged attacker cannot create this precondition, and enabling NEXT_BUDDY is rare in practice, so success depends on system state outside the attacker\u0027s control.\nPR:L - Given a system with NEXT_BUDDY enabled, no special capability is needed \u2014 any unprivileged task\u0027s ordinary sleep/wake and the kernel\u0027s own load balancer (attach_task()/move_queued_task() calling wakeup_preempt() on a still-sched_delayed task) drive the code path. Only the ability to run an unprivileged process is required.\nUI:N - No victim action is needed; the reporter observed the WARN triggering instantly on ordinary system activity once the feature was enabled. Normal scheduling and CPU load balancing reach the faulty path on their own.\nS:U - The corrupted state is the kernel\u0027s own per-CPU cfs_rq bookkeeping and sched_entity flags, all within the kernel\u0027s security authority. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - The scheduler is left able to run an entity that is simultaneously marked sched_delayed and blocked, which desynchronizes on_rq/nr_running/load.weight and can drive __dequeue_entity() to rb_erase an already-unlinked node, writing through a stale rb_parent pointer into memory that may have been reused. Such scheduler-structure corruption is leverageable toward reading kernel memory contents.\nI:H - A task in a non-RUNNING state is made to execute \u2014 a direct violation of a core scheduling invariant \u2014 and the resulting sched_delayed/on_rq desync leads to double account_entity_dequeue() (nr_running and load.weight underflow) and rb_erase on an unlinked rbtree node, giving a write primitive over scheduler-adjacent memory rather than a mere miscount.\nA:H - pick_next_entity() fires WARN_ONCE, which is a full kernel panic on the panic_on_warn=1 configurations used by hardened and CI deployments, and further SCHED_WARN_ONs cascade in dequeue_entity()/dequeue_entities(). Beyond the splat, the runqueue accounting underflow and rbtree corruption destabilize scheduling on the affected CPU, causing starvation, hangs, and crashes."
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        "dateUpdated": "2026-08-05T11:40:03.481Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2024-49573",
    "datePublished": "2025-01-11T12:35:37.625Z",
    "dateReserved": "2025-01-11T12:32:49.536Z",
    "dateUpdated": "2026-08-05T11:40:03.481Z",
    "state": "PUBLISHED"
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      "id": "CVE-2024-49573",
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      "published": "2025-01-11T13:15:24.223",
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      "vulnStatus": "Received"
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    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2025-11-25T09:01:08+00:00",
      "cve": "CVE-2024-49573",
      "id": "CVE-2024-49573",
      "initial_release_date": "2024-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "276",
      "source": "Red Hat CSAF VEX",
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      "title": "kernel: sched/fair: Fix NEXT_BUDDY",
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      "version": "3"
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      "current_release_date": "2026-08-22T01:30:06Z",
      "cve": "CVE-2024-49573",
      "id": "CVE-2024-49573",
      "initial_release_date": "2025-01-12T00:17:49Z",
      "product_status:known_not_affected": "346",
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      "title": "SUSE CVE CVE-2024-49573",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2024-49573.json",
      "version": "24"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.


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.