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CVE-2026-72036 (GCVE-0-2026-72036)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:51 – Updated: 2026-08-17 05:39
VLAI
Title
net/sched: sch_multiq: Replace direct dequeue call with peek and qdisc_dequeue_peeked
Summary
In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_multiq: Replace direct dequeue call with peek and qdisc_dequeue_peeked multiq_dequeue() takes a packet from a band's child with a direct ->dequeue() call after multiq_peek() peeked it. When the child is non-work-conserving the peek stashes the skb in the child's gso_skb, so the direct dequeue returns a different skb and orphans the stash, desyncing the child's qlen/backlog. With a qfq child reached through a peeking parent (e.g. tbf) this re-enters the child on an emptied list and dereferences NULL, panicking the kernel from softirq on ordinary egress. Take the packet through qdisc_dequeue_peeked(), as sch_prio already does and as sch_red and sch_sfb were just fixed to do. The helper is a no-op when the child has no stash, so a work-conserving child is unaffected.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 , < 3e5fd9d14f2d228e7260251f2e4a1d41ba8f705a (git)
Affected: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 , < eb1a9637f0bd84b5db8803af65dfb1f44785406f (git)
Affected: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 , < 7a5a1582710981ef6637de9f074a60a5b1d63222 (git)
Affected: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 , < 86a61e46a1919e8abf4d227c204773dabb24068a (git)
Affected: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 , < 1b9cc255e8089606b92b2adf504e334573682821 (git)
Affected: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 , < 5889064919a1e5c0a9469c54895000414fc46944 (git)
Affected: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 , < fffeb2ab5eeb823d4c2330571a098f63237c9049 (git)
Affected: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 , < 54f6b0c843e228d499eb4b6bbb89df68cad9ad5d (git)
guessed Create a notification for this product.
Linux Linux Affected: 2.6.29
Unaffected: 0 , < 2.6.29 (semver)
Unaffected: 5.10.261 , ≤ 5.10.* (semver)
Unaffected: 5.15.212 , ≤ 5.15.* (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_multiq: Replace direct dequeue call with peek and qdisc_dequeue_peeked\n\nmultiq_dequeue() takes a packet from a band\u0027s child with a direct\n-\u003edequeue() call after multiq_peek() peeked it. When the child is\nnon-work-conserving the peek stashes the skb in the child\u0027s gso_skb, so\nthe direct dequeue returns a different skb and orphans the stash,\ndesyncing the child\u0027s qlen/backlog. With a qfq child reached through a\npeeking parent (e.g. tbf) this re-enters the child on an emptied list and\ndereferences NULL, panicking the kernel from softirq on ordinary egress.\n\nTake the packet through qdisc_dequeue_peeked(), as sch_prio already does\nand as sch_red and sch_sfb were just fixed to do. The helper is a no-op\nwhen the child has no stash, so a work-conserving child is unaffected."
        }
      ],
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Exploitation requires locally installing a tbf\u2192multiq\u2192qfq hierarchy on a multiqueue netdev via RTM_NEWQDISC/tc netlink before egress can hit multiq_dequeue(); per kernel CNA guidance, tc/qdisc configuration bugs are Local even though the panic fires from softirq during packet transmission.\nAC:L - Once the hierarchy exists, the peek/dequeue mismatch is a deterministic logic bug: tbf peek stashes the QFQ child\u0027s skb in gso_skb, then multiq_dequeue\u0027s direct child-\u003edequeue() bypasses that stash and re-enters QFQ on an emptied list; ping reproducers for sch_red/sfb show no race or layout dependency.\nPR:L - RTM_NEWQDISC and qdisc grafting are gated by netlink_net_capable(skb, CAP_NET_ADMIN) in rtnetlink_rcv_msg, evaluated against net-\u003euser_ns; unprivileged users obtain CAP_NET_ADMIN via user/network namespaces (unshare -Urn) without init-namespace root.\nUI:N - No victim interaction is needed after qdisc setup; triggering the NULL dereference requires only attacker-generated egress traffic (e.g., ping) through the defective tbf\u2192multiq\u2192qfq dequeue path.\nS:U - The qlen/backlog desync, orphaned gso_skb stash, and resulting kernel panic occur entirely within the host kernel packet scheduler; no VM, IOMMU, or sandbox security boundary is crossed.\nC:H - Peek stashes the skb in the non-work-conserving child\u0027s gso_skb while direct dequeue returns a different packet, desyncing qlen/backlog\u2014the same scheduler-accounting corruption primitive seen in prior net/sched CVEs and capable of exposing corrupted or freed kernel scheduler memory.\nI:H - Orphaning the gso_skb stash corrupts parent/child queue linkage and QFQ aggregate scheduling state; inconsistent qlen drives invalid list operations in qfq_dequeue, yielding attacker-influenced memory corruption beyond the demonstrated NULL dereference.\nA:H - The desync re-enters QFQ on an emptied aggregate list and dereferences NULL in qfq_dequeue from softirq during ordinary egress, panicking the kernel as documented in the fix commit and matching KASAN null-ptr-deref traces in the related sch_red/sch_sfb reports."
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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      "title": "net/sched: sch_multiq: Replace direct dequeue call with peek and qdisc_dequeue_peeked",
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    "cveId": "CVE-2026-72036",
    "datePublished": "2026-08-15T05:51:57.012Z",
    "dateReserved": "2026-08-09T03:40:39.901Z",
    "dateUpdated": "2026-08-17T05:39:39.361Z",
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With a qfq child reached through a\\npeeking parent (e.g. tbf) this re-enters the child on an emptied list and\\ndereferences NULL, panicking the kernel from softirq on ordinary egress.\\n\\nTake the packet through qdisc_dequeue_peeked(), as sch_prio already does\\nand as sch_red and sch_sfb were just fixed to do. The helper is a no-op\\nwhen the child has no stash, so a work-conserving child is unaffected.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/sched/sch_multiq.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"77be155cba4e163e8bba9fd27222a8b6189ec4f7\",\"lessThan\":\"3e5fd9d14f2d228e7260251f2e4a1d41ba8f705a\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"77be155cba4e163e8bba9fd27222a8b6189ec4f7\",\"lessThan\":\"eb1a9637f0bd84b5db8803af65dfb1f44785406f\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"77be155cba4e163e8bba9fd27222a8b6189ec4f7\",\"lessThan\":\"7a5a1582710981ef6637de9f074a60a5b1d63222\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"77be155cba4e163e8bba9fd27222a8b6189ec4f7\",\"lessThan\":\"86a61e46a1919e8abf4d227c204773dabb24068a\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"77be155cba4e163e8bba9fd27222a8b6189ec4f7\",\"lessThan\":\"1b9cc255e8089606b92b2adf504e334573682821\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"77be155cba4e163e8bba9fd27222a8b6189ec4f7\",\"lessThan\":\"5889064919a1e5c0a9469c54895000414fc46944\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"77be155cba4e163e8bba9fd27222a8b6189ec4f7\",\"lessThan\":\"fffeb2ab5eeb823d4c2330571a098f63237c9049\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"77be155cba4e163e8bba9fd27222a8b6189ec4f7\",\"lessThan\":\"54f6b0c843e228d499eb4b6bbb89df68cad9ad5d\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/sched/sch_multiq.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"2.6.29\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"2.6.29\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.10.261\",\"lessThanOrEqual\":\"5.10.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.212\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.178\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.145\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.97\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.40\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/1b9cc255e8089606b92b2adf504e334573682821\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/3e5fd9d14f2d228e7260251f2e4a1d41ba8f705a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/54f6b0c843e228d499eb4b6bbb89df68cad9ad5d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/5889064919a1e5c0a9469c54895000414fc46944\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7a5a1582710981ef6637de9f074a60a5b1d63222\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/86a61e46a1919e8abf4d227c204773dabb24068a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/eb1a9637f0bd84b5db8803af65dfb1f44785406f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/fffeb2ab5eeb823d4c2330571a098f63237c9049\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-18T11:34:31+00:00",
      "cve": "CVE-2026-72036",
      "id": "CVE-2026-72036",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net/sched: sch_multiq: Replace direct dequeue call with peek and qdisc_dequeue_peeked",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72036.json",
      "version": "3"
    }
  }
}



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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

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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.
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  • 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.