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GHSA-6MV6-43G2-7QMW

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33
VLAI
Details

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
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{
  "affected": [],
  "aliases": [
    "CVE-2026-72036"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:21:12Z",
    "severity": "HIGH"
  },
  "details": "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.",
  "id": "GHSA-6mv6-43g2-7qmw",
  "modified": "2026-08-17T06:33:06Z",
  "published": "2026-08-15T06:32:09Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72036"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1b9cc255e8089606b92b2adf504e334573682821"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3e5fd9d14f2d228e7260251f2e4a1d41ba8f705a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/54f6b0c843e228d499eb4b6bbb89df68cad9ad5d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5889064919a1e5c0a9469c54895000414fc46944"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7a5a1582710981ef6637de9f074a60a5b1d63222"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/86a61e46a1919e8abf4d227c204773dabb24068a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eb1a9637f0bd84b5db8803af65dfb1f44785406f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fffeb2ab5eeb823d4c2330571a098f63237c9049"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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