CVE-2026-72036 (GCVE-0-2026-72036)
Vulnerability from cvelistv5
Published
2026-08-15 05:51
Modified
2026-08-17 05:39
Severity ?
VLAI Severity ?
EPSS score ?
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.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 Version: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 Version: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 Version: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 Version: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 Version: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 Version: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 Version: 77be155cba4e163e8bba9fd27222a8b6189ec4f7 |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/sched/sch_multiq.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
"version": "77be155cba4e163e8bba9fd27222a8b6189ec4f7",
"versionType": "git"
},
{
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{
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"programFiles": [
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.29"
},
{
"lessThan": "2.6.29",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.261",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
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"versionEndExcluding": "5.10.261",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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{
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{
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{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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},
{
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{
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"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"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."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"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."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:39:39.361Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/3e5fd9d14f2d228e7260251f2e4a1d41ba8f705a"
},
{
"url": "https://git.kernel.org/stable/c/eb1a9637f0bd84b5db8803af65dfb1f44785406f"
},
{
"url": "https://git.kernel.org/stable/c/7a5a1582710981ef6637de9f074a60a5b1d63222"
},
{
"url": "https://git.kernel.org/stable/c/86a61e46a1919e8abf4d227c204773dabb24068a"
},
{
"url": "https://git.kernel.org/stable/c/1b9cc255e8089606b92b2adf504e334573682821"
},
{
"url": "https://git.kernel.org/stable/c/5889064919a1e5c0a9469c54895000414fc46944"
},
{
"url": "https://git.kernel.org/stable/c/fffeb2ab5eeb823d4c2330571a098f63237c9049"
},
{
"url": "https://git.kernel.org/stable/c/54f6b0c843e228d499eb4b6bbb89df68cad9ad5d"
}
],
"title": "net/sched: sch_multiq: Replace direct dequeue call with peek and qdisc_dequeue_peeked",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"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",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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