CVE-2026-80630 (GCVE-0-2026-80630)
Vulnerability from cvelistv5
Published
2026-08-28 06:48
Modified
2026-08-29 06:21
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_fq_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen
Whenever fq_codel drops packets during peek, it calls
qdisc_tree_reduce_backlog. An issue arises because it calls
qdisc_tree_reduce_backlog before it reincrements the qlen. If qlen drops
to zero, but peek returns an skb, the parent's qlen_notify callback will be
executed even though fq_codel still has 1 packet on the queue and, thus,
will mistakenly deactivate the parent's class causing issues like a recent
report [1] and a wild memory access in qfq:
[ 29.371146][ T360] Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI
[ 29.371666][ T360] KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127]
[ 29.371987][ T360] CPU: 6 UID: 0 PID: 360 Comm: tc Not tainted 7.1.0-rc5-00285-gc530e5b2dbc6-dirty #82 PREEMPT(full)
[ 29.372384][ T360] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 29.372620][ T360] RIP: 0010:qfq_deactivate_agg (include/linux/list.h:1029 (discriminator 2) include/linux/list.h:1043 (discriminator 2) net/sched/sch_qfq.c:1369 (discriminator 2) net/sched/sch_qfq.c:1395 (discriminator 2)) sch_qfq
[ 29.373544][ T360] RSP: 0018:ffff888102417370 EFLAGS: 00010216
[ 29.373800][ T360] RAX: 0000000000000000 RBX: ffff88811224d568 RCX: dffffc0000000000
[ 29.374079][ T360] RDX: 1ffff11021fe1543 RSI: ffff88810ff0aa00 RDI: dffffc0000000000
[ 29.374368][ T360] RBP: ffff88811224c280 R08: dead000000000122 R09: 1bd5a00000000024
[ 29.374649][ T360] R10: fffffbfff7940329 R11: fffffbfff7940329 R12: 0000000000000000
[ 29.374926][ T360] R13: dead000000000100 R14: ffff88811224d580 R15: ffff88811224d578
[ 29.375207][ T360] FS: 00007f5b794e5780(0000) GS:ffff88815d1e9000(0000) knlGS:0000000000000000
[ 29.375545][ T360] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 29.375823][ T360] CR2: 000055ffb091f000 CR3: 000000010a305000 CR4: 0000000000750ef0
[ 29.376103][ T360] PKRU: 55555554
[ 29.376258][ T360] Call Trace:
[ 29.376401][ T360] <TASK>
...
[ 29.376885][ T360] qfq_reset_qdisc (net/sched/sch_qfq.c:357 net/sched/sch_qfq.c:1487) sch_qfq
[ 29.377074][ T360] qdisc_reset (net/sched/sch_generic.c:1057)
[ 29.377414][ T360] __qdisc_destroy (net/sched/sch_generic.c:1096)
[ 29.377600][ T360] qdisc_graft (net/sched/sch_api.c:1062 net/sched/sch_api.c:1053 net/sched/sch_api.c:1159)
[ 29.378593][ T360] tc_get_qdisc (net/sched/sch_api.c:1528 net/sched/sch_api.c:1556)
Fix this by only calling qdisc_tree_reduce_backlog in peek after the
qlen is restored.
[1] http://lore.kernel.org/netdev/CAN2cbVe79oj0O9==m4+4x3v+O+qzRagA=2=wkrp9i9=CqYvyZA@mail.gmail.com/
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: cc71a757da78dd4aa1b4a9b19cb011833730ccf2 Version: eda741fe155ddf5ecd2dd3bfbd4fc3c0c7dbb450 Version: 829c49b6b2ff45b043739168fd1245e4e1a91a30 Version: 2f9761a94bae33d26e6a81b31b36e7d776d93dc1 Version: 4d55144b12e742404bb3f8fee6038bafbf45619d Version: 342debc12183b51773b3345ba267e9263bdfaaef Version: 342debc12183b51773b3345ba267e9263bdfaaef Version: 342debc12183b51773b3345ba267e9263bdfaaef Version: 7a742a9506849d1c1aa71e36c89855ceddc7d58e Version: e73c838c80dccb9e4f19becc11d9f3cb4a27d483 Version: a57fe60ef4cf96bfbb6b58397ec28bdb5a5c6b31 Version: 5.10.241 ≤ Version: 5.15.190 ≤ Version: 6.1.135 ≤ Version: 6.6.88 ≤ Version: 6.12.24 ≤ Version: 5.4.297 ≤ Version: 6.13.12 ≤ Version: 6.14.3 ≤ |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/sched/sch_fq_codel.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "3e515188393e62a718ccebee651ee74514104ff6",
"status": "affected",
"version": "cc71a757da78dd4aa1b4a9b19cb011833730ccf2",
"versionType": "git"
},
{
"lessThan": "20dd591d8f951e1e6aca5052be8785e6181055e2",
"status": "affected",
"version": "eda741fe155ddf5ecd2dd3bfbd4fc3c0c7dbb450",
"versionType": "git"
},
{
"lessThan": "94a5f1efdefb01f82cd228bf4e7ef1e8fc075c80",
"status": "affected",
"version": "829c49b6b2ff45b043739168fd1245e4e1a91a30",
"versionType": "git"
},
{
"lessThan": "acc08a0c7f37ebb1901144e03a7cba7d4afd9203",
"status": "affected",
"version": "2f9761a94bae33d26e6a81b31b36e7d776d93dc1",
"versionType": "git"
},
{
"lessThan": "7c09843fd2b44d9bf0de798683861d1aecd62a08",
"status": "affected",
"version": "4d55144b12e742404bb3f8fee6038bafbf45619d",
"versionType": "git"
},
{
"lessThan": "0500af8630c3253f0dde879bd3a73a06bb2f2b3f",
"status": "affected",
"version": "342debc12183b51773b3345ba267e9263bdfaaef",
"versionType": "git"
},
{
"lessThan": "af54df2f44d9605614bc7ed96640302a240a9a62",
"status": "affected",
"version": "342debc12183b51773b3345ba267e9263bdfaaef",
"versionType": "git"
},
{
"lessThan": "097f6fc7b1ae362dd7a9444b2572162fda73b284",
"status": "affected",
"version": "342debc12183b51773b3345ba267e9263bdfaaef",
"versionType": "git"
},
{
"status": "affected",
"version": "7a742a9506849d1c1aa71e36c89855ceddc7d58e",
"versionType": "git"
},
{
"status": "affected",
"version": "e73c838c80dccb9e4f19becc11d9f3cb4a27d483",
"versionType": "git"
},
{
"status": "affected",
"version": "a57fe60ef4cf96bfbb6b58397ec28bdb5a5c6b31",
"versionType": "git"
},
{
"lessThan": "5.10.261",
"status": "affected",
"version": "5.10.241",
"versionType": "semver"
},
{
"lessThan": "5.15.212",
"status": "affected",
"version": "5.15.190",
"versionType": "semver"
},
{
"lessThan": "6.1.178",
"status": "affected",
"version": "6.1.135",
"versionType": "semver"
},
{
"lessThan": "6.6.145",
"status": "affected",
"version": "6.6.88",
"versionType": "semver"
},
{
"lessThan": "6.12.97",
"status": "affected",
"version": "6.12.24",
"versionType": "semver"
},
{
"lessThan": "5.5",
"status": "affected",
"version": "5.4.297",
"versionType": "semver"
},
{
"lessThan": "6.14",
"status": "affected",
"version": "6.13.12",
"versionType": "semver"
},
{
"lessThan": "6.15",
"status": "affected",
"version": "6.14.3",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/sched/sch_fq_codel.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.15"
},
{
"lessThan": "6.15",
"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": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.261",
"versionStartIncluding": "5.10.241",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.212",
"versionStartIncluding": "5.15.190",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.178",
"versionStartIncluding": "6.1.135",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.145",
"versionStartIncluding": "6.6.88",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.97",
"versionStartIncluding": "6.12.24",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.40",
"versionStartIncluding": "6.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.5",
"versionStartIncluding": "6.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "6.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.4.297",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.13.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.14.3",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_fq_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen\n\nWhenever fq_codel drops packets during peek, it calls\nqdisc_tree_reduce_backlog. An issue arises because it calls\nqdisc_tree_reduce_backlog before it reincrements the qlen. If qlen drops\nto zero, but peek returns an skb, the parent\u0027s qlen_notify callback will be\nexecuted even though fq_codel still has 1 packet on the queue and, thus,\nwill mistakenly deactivate the parent\u0027s class causing issues like a recent\nreport [1] and a wild memory access in qfq:\n\n[ 29.371146][ T360] Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI\n[ 29.371666][ T360] KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127]\n[ 29.371987][ T360] CPU: 6 UID: 0 PID: 360 Comm: tc Not tainted 7.1.0-rc5-00285-gc530e5b2dbc6-dirty #82 PREEMPT(full)\n[ 29.372384][ T360] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011\n[ 29.372620][ T360] RIP: 0010:qfq_deactivate_agg (include/linux/list.h:1029 (discriminator 2) include/linux/list.h:1043 (discriminator 2) net/sched/sch_qfq.c:1369 (discriminator 2) net/sched/sch_qfq.c:1395 (discriminator 2)) sch_qfq\n[ 29.373544][ T360] RSP: 0018:ffff888102417370 EFLAGS: 00010216\n[ 29.373800][ T360] RAX: 0000000000000000 RBX: ffff88811224d568 RCX: dffffc0000000000\n[ 29.374079][ T360] RDX: 1ffff11021fe1543 RSI: ffff88810ff0aa00 RDI: dffffc0000000000\n[ 29.374368][ T360] RBP: ffff88811224c280 R08: dead000000000122 R09: 1bd5a00000000024\n[ 29.374649][ T360] R10: fffffbfff7940329 R11: fffffbfff7940329 R12: 0000000000000000\n[ 29.374926][ T360] R13: dead000000000100 R14: ffff88811224d580 R15: ffff88811224d578\n[ 29.375207][ T360] FS: 00007f5b794e5780(0000) GS:ffff88815d1e9000(0000) knlGS:0000000000000000\n[ 29.375545][ T360] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[ 29.375823][ T360] CR2: 000055ffb091f000 CR3: 000000010a305000 CR4: 0000000000750ef0\n[ 29.376103][ T360] PKRU: 55555554\n[ 29.376258][ T360] Call Trace:\n[ 29.376401][ T360] \u003cTASK\u003e\n...\n[ 29.376885][ T360] qfq_reset_qdisc (net/sched/sch_qfq.c:357 net/sched/sch_qfq.c:1487) sch_qfq\n[ 29.377074][ T360] qdisc_reset (net/sched/sch_generic.c:1057)\n[ 29.377414][ T360] __qdisc_destroy (net/sched/sch_generic.c:1096)\n[ 29.377600][ T360] qdisc_graft (net/sched/sch_api.c:1062 net/sched/sch_api.c:1053 net/sched/sch_api.c:1159)\n[ 29.378593][ T360] tc_get_qdisc (net/sched/sch_api.c:1528 net/sched/sch_api.c:1556)\n\nFix this by only calling qdisc_tree_reduce_backlog in peek after the\nqlen is restored.\n\n[1] http://lore.kernel.org/netdev/CAN2cbVe79oj0O9==m4+4x3v+O+qzRagA=2=wkrp9i9=CqYvyZA@mail.gmail.com/"
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - Remote senders reach the bug when packets traverse a QFQ or other qlen_notify parent with an fq_codel child: qfq_enqueue() and qfq_dequeue() call the child peek handler during __dev_queue_xmit egress scheduling, and CoDel can drop there before qlen is restored.\nAC:L - The attacker controls traffic rate, packet size, and CoDel drop behavior to force drops during peek while qlen reads zero; this is a deterministic logic bug, not a race on uncontrollable kernel state or a rare compile-time configuration.\nPR:N - On systems where an operator has already deployed a parent qdisc with an fq_codel leaf, any remote party that can send packets into the shaped class can trigger the faulty peek/drop path with no account or capabilities on the victim host.\nUI:N - Exploitation requires only attacker-generated traffic to drive peek-time CoDel drops through the installed hierarchy; no independent action by another user or administrator is needed at trigger time.\nS:U - The flaw corrupts in-kernel QFQ/fq_codel scheduler structures and memory within the same kernel security domain; it does not cross VM, container, or IOMMU authority boundaries.\nC:H - False qlen_notify prematurely deactivates QFQ aggregates while packets remain; the fix commit shows KASAN wild-memory-access on poisoned aggregate list nodes in qfq_deactivate_agg(), giving attacker-influenced reads from freed/corrupted scheduler memory.\nI:H - Corrupted aggregate/class linkage leads to invalid hlist operations and inconsistent scheduler state that can be steered with heap layout control, yielding memory corruption primitives usable for arbitrary kernel writes or control-flow hijack.\nA:H - The published oops is a general protection fault from corrupted QFQ state during qdisc teardown, and the same corruption during live packet scheduling can reliably kernel-panic or hang affected hosts."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-29T06:21:30.275Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/3e515188393e62a718ccebee651ee74514104ff6"
},
{
"url": "https://git.kernel.org/stable/c/20dd591d8f951e1e6aca5052be8785e6181055e2"
},
{
"url": "https://git.kernel.org/stable/c/94a5f1efdefb01f82cd228bf4e7ef1e8fc075c80"
},
{
"url": "https://git.kernel.org/stable/c/acc08a0c7f37ebb1901144e03a7cba7d4afd9203"
},
{
"url": "https://git.kernel.org/stable/c/7c09843fd2b44d9bf0de798683861d1aecd62a08"
},
{
"url": "https://git.kernel.org/stable/c/0500af8630c3253f0dde879bd3a73a06bb2f2b3f"
},
{
"url": "https://git.kernel.org/stable/c/af54df2f44d9605614bc7ed96640302a240a9a62"
},
{
"url": "https://git.kernel.org/stable/c/097f6fc7b1ae362dd7a9444b2572162fda73b284"
}
],
"title": "net/sched: sch_fq_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-80630",
"datePublished": "2026-08-28T06:48:46.569Z",
"dateReserved": "2026-08-26T14:34:25.776Z",
"dateUpdated": "2026-08-29T06:21:30.275Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
Loading…
Loading…
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.
Loading…
Loading…