CVE-2026-23340 (GCVE-0-2026-23340)
Vulnerability from cvelistv5 – Published: 2026-03-25 10:27 – Updated: 2026-09-08 08:45
VLAI
EPSS
VEX
Title
net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs
Summary
In the Linux kernel, the following vulnerability has been resolved:
net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs
When shrinking the number of real tx queues,
netif_set_real_num_tx_queues() calls qdisc_reset_all_tx_gt() to flush
qdiscs for queues which will no longer be used.
qdisc_reset_all_tx_gt() currently serializes qdisc_reset() with
qdisc_lock(). However, for lockless qdiscs, the dequeue path is
serialized by qdisc_run_begin/end() using qdisc->seqlock instead, so
qdisc_reset() can run concurrently with __qdisc_run() and free skbs
while they are still being dequeued, leading to UAF.
This can easily be reproduced on e.g. virtio-net by imposing heavy
traffic while frequently changing the number of queue pairs:
iperf3 -ub0 -c $peer -t 0 &
while :; do
ethtool -L eth0 combined 1
ethtool -L eth0 combined 2
done
With KASAN enabled, this leads to reports like:
BUG: KASAN: slab-use-after-free in __qdisc_run+0x133f/0x1760
...
Call Trace:
<TASK>
...
__qdisc_run+0x133f/0x1760
__dev_queue_xmit+0x248f/0x3550
ip_finish_output2+0xa42/0x2110
ip_output+0x1a7/0x410
ip_send_skb+0x2e6/0x480
udp_send_skb+0xb0a/0x1590
udp_sendmsg+0x13c9/0x1fc0
...
</TASK>
Allocated by task 1270 on cpu 5 at 44.558414s:
...
alloc_skb_with_frags+0x84/0x7c0
sock_alloc_send_pskb+0x69a/0x830
__ip_append_data+0x1b86/0x48c0
ip_make_skb+0x1e8/0x2b0
udp_sendmsg+0x13a6/0x1fc0
...
Freed by task 1306 on cpu 3 at 44.558445s:
...
kmem_cache_free+0x117/0x5e0
pfifo_fast_reset+0x14d/0x580
qdisc_reset+0x9e/0x5f0
netif_set_real_num_tx_queues+0x303/0x840
virtnet_set_channels+0x1bf/0x260 [virtio_net]
ethnl_set_channels+0x684/0xae0
ethnl_default_set_doit+0x31a/0x890
...
Serialize qdisc_reset_all_tx_gt() against the lockless dequeue path by
taking qdisc->seqlock for TCQ_F_NOLOCK qdiscs, matching the
serialization model already used by dev_reset_queue().
Additionally clear QDISC_STATE_NON_EMPTY after reset so the qdisc state
reflects an empty queue, avoiding needless re-scheduling.
Severity
7.8 (High)
Assigner
References
9 references
Impacted products
8 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7 , < 5bb27ad54d12de67e457d7d251198e361bef835e
(git)
Affected: 6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7 , < 7594467c49bfc2f4644dee0415ac2290db11fa0d (git) Affected: 6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7 , < dbd58b0730aa06ab6ad26079cf9a5b6b58e7e750 (git) Affected: 6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7 , < 5bc4e69306ed7ae02232eb4c0b23ed621a26d504 (git) Affected: 6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7 , < 8314944cc3bdeaa5a73e6f8a8cf0d94822e625cb (git) Affected: 6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7 , < c69df4e0524f8de8e176ba389acd83e85f5f49d0 (git) Affected: 6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7 , < 7f083faf59d14c04e01ec05a7507f036c965acf8 (git) |
guessed | |
| Linux | Linux |
Affected:
4.16
Unaffected: 0 , < 4.16 (semver) Unaffected: 5.15.203 , ≤ 5.15.* (semver) Unaffected: 6.1.167 , ≤ 6.1.* (semver) Unaffected: 6.6.130 , ≤ 6.6.* (semver) Unaffected: 6.12.77 , ≤ 6.12.* (semver) Unaffected: 6.18.17 , ≤ 6.18.* (semver) Unaffected: 6.19.7 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix) |
guessed | |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP |
Affected:
V3.1.6 , < *
(custom)
|
guessed | |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP |
Affected:
V3.1.5 , < *
(custom)
|
guessed | |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP |
Affected:
V3.1.6 , < *
(custom)
|
guessed | |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP |
Affected:
V3.1.5 , < *
(custom)
|
guessed | |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP |
Affected:
V3.1.6 , < *
(custom)
|
guessed | |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP |
Affected:
V3.1.5 , < *
(custom)
|
guessed |
{
"containers": {
"adp": [
{
"affected": [
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-08T08:45:39.039Z",
"orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
"shortName": "siemens-SADP"
},
"references": [
{
"url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"
},
{
"url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
}
],
"x_adpType": "supplier"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"include/net/sch_generic.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "5bb27ad54d12de67e457d7d251198e361bef835e",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
},
{
"lessThan": "7594467c49bfc2f4644dee0415ac2290db11fa0d",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
},
{
"lessThan": "dbd58b0730aa06ab6ad26079cf9a5b6b58e7e750",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
},
{
"lessThan": "5bc4e69306ed7ae02232eb4c0b23ed621a26d504",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
},
{
"lessThan": "8314944cc3bdeaa5a73e6f8a8cf0d94822e625cb",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
},
{
"lessThan": "c69df4e0524f8de8e176ba389acd83e85f5f49d0",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
},
{
"lessThan": "7f083faf59d14c04e01ec05a7507f036c965acf8",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"include/net/sch_generic.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.16"
},
{
"lessThan": "4.16",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.167",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.130",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.77",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.17",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.7",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.203",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.167",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.130",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.77",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.17",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.19.7",
"versionStartIncluding": "4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.0",
"versionStartIncluding": "4.16",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs\n\nWhen shrinking the number of real tx queues,\nnetif_set_real_num_tx_queues() calls qdisc_reset_all_tx_gt() to flush\nqdiscs for queues which will no longer be used.\n\nqdisc_reset_all_tx_gt() currently serializes qdisc_reset() with\nqdisc_lock(). However, for lockless qdiscs, the dequeue path is\nserialized by qdisc_run_begin/end() using qdisc-\u003eseqlock instead, so\nqdisc_reset() can run concurrently with __qdisc_run() and free skbs\nwhile they are still being dequeued, leading to UAF.\n\nThis can easily be reproduced on e.g. virtio-net by imposing heavy\ntraffic while frequently changing the number of queue pairs:\n\n iperf3 -ub0 -c $peer -t 0 \u0026\n while :; do\n ethtool -L eth0 combined 1\n ethtool -L eth0 combined 2\n done\n\nWith KASAN enabled, this leads to reports like:\n\n BUG: KASAN: slab-use-after-free in __qdisc_run+0x133f/0x1760\n ...\n Call Trace:\n \u003cTASK\u003e\n ...\n __qdisc_run+0x133f/0x1760\n __dev_queue_xmit+0x248f/0x3550\n ip_finish_output2+0xa42/0x2110\n ip_output+0x1a7/0x410\n ip_send_skb+0x2e6/0x480\n udp_send_skb+0xb0a/0x1590\n udp_sendmsg+0x13c9/0x1fc0\n ...\n \u003c/TASK\u003e\n\n Allocated by task 1270 on cpu 5 at 44.558414s:\n ...\n alloc_skb_with_frags+0x84/0x7c0\n sock_alloc_send_pskb+0x69a/0x830\n __ip_append_data+0x1b86/0x48c0\n ip_make_skb+0x1e8/0x2b0\n udp_sendmsg+0x13a6/0x1fc0\n ...\n\n Freed by task 1306 on cpu 3 at 44.558445s:\n ...\n kmem_cache_free+0x117/0x5e0\n pfifo_fast_reset+0x14d/0x580\n qdisc_reset+0x9e/0x5f0\n netif_set_real_num_tx_queues+0x303/0x840\n virtnet_set_channels+0x1bf/0x260 [virtio_net]\n ethnl_set_channels+0x684/0xae0\n ethnl_default_set_doit+0x31a/0x890\n ...\n\nSerialize qdisc_reset_all_tx_gt() against the lockless dequeue path by\ntaking qdisc-\u003eseqlock for TCQ_F_NOLOCK qdiscs, matching the\nserialization model already used by dev_reset_queue().\n\nAdditionally clear QDISC_STATE_NON_EMPTY after reset so the qdisc state\nreflects an empty queue, avoiding needless re-scheduling."
}
],
"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 - Triggered via ethtool netlink (ETHTOOL_MSG_CHANNELS_SET) which requires local access through a netlink socket. Not reachable from the network.\nAC:L - The attacker controls both sides of the race \u2014 sending traffic and changing channel count simultaneously. The commit message confirms this is \"easily reproduced\" with concurrent iperf and ethtool.\nPR:L - ETHTOOL_MSG_CHANNELS_SET uses GENL_UNS_ADMIN_PERM, which checks CAP_NET_ADMIN in the user namespace via netlink_ns_capable(). Veth devices support set_channels and can be created in user namespaces, so an unprivileged user can trigger this via unshare -Urn.\nUI:N - No user interaction is required. The attacker can independently trigger both the traffic and channel reconfiguration.\nS:U - Standard kernel use-after-free within the same security authority (kernel). No cross-boundary impact like VM escape.\nC:H - This is a use-after-free on sk_buff objects. The freed skb memory can be reallocated with attacker-controlled content, enabling reading of arbitrary kernel memory through the dangling pointer.\nI:H - UAF on sk_buff objects allows heap spraying \u2014 the freed skb slab can be reclaimed with attacker-controlled data, enabling arbitrary write primitives and potential code execution.\nA:H - The KASAN report confirms a slab-use-after-free crash in __qdisc_run. This causes a kernel oops/panic, and is easily and repeatedly triggerable."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-05T12:21:14.647Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/5bb27ad54d12de67e457d7d251198e361bef835e"
},
{
"url": "https://git.kernel.org/stable/c/7594467c49bfc2f4644dee0415ac2290db11fa0d"
},
{
"url": "https://git.kernel.org/stable/c/dbd58b0730aa06ab6ad26079cf9a5b6b58e7e750"
},
{
"url": "https://git.kernel.org/stable/c/5bc4e69306ed7ae02232eb4c0b23ed621a26d504"
},
{
"url": "https://git.kernel.org/stable/c/8314944cc3bdeaa5a73e6f8a8cf0d94822e625cb"
},
{
"url": "https://git.kernel.org/stable/c/c69df4e0524f8de8e176ba389acd83e85f5f49d0"
},
{
"url": "https://git.kernel.org/stable/c/7f083faf59d14c04e01ec05a7507f036c965acf8"
}
],
"title": "net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-23340",
"datePublished": "2026-03-25T10:27:28.728Z",
"dateReserved": "2026-01-13T15:37:45.998Z",
"dateUpdated": "2026-09-08T08:45:39.039Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-23340",
"date": "2026-09-29",
"epss": "0.00137",
"percentile": "0.02572"
},
"microsoft_vex": {
"current_release_date": "2026-04-25T01:04:57.000Z",
"cve": "CVE-2026-23340",
"id": "msrc_CVE-2026-23340",
"initial_release_date": "2026-03-02T00:00:00.000Z",
"product_status:fixed": "1",
"product_status:known_affected": "2",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-23340.json",
"version": "3"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"include/net/sch_generic.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "5bb27ad54d12de67e457d7d251198e361bef835e",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
},
{
"lessThan": "7594467c49bfc2f4644dee0415ac2290db11fa0d",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
},
{
"lessThan": "dbd58b0730aa06ab6ad26079cf9a5b6b58e7e750",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
},
{
"lessThan": "5bc4e69306ed7ae02232eb4c0b23ed621a26d504",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
},
{
"lessThan": "8314944cc3bdeaa5a73e6f8a8cf0d94822e625cb",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
},
{
"lessThan": "c69df4e0524f8de8e176ba389acd83e85f5f49d0",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
},
{
"lessThan": "7f083faf59d14c04e01ec05a7507f036c965acf8",
"status": "affected",
"version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"include/net/sch_generic.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.16"
},
{
"lessThan": "4.16",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.167",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.130",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.77",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.17",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.7",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"affectedData": [
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.5",
"versionType": "custom"
}
]
}
],
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "2084F3CA-9155-4C25-AE7F-A6BC24B53E24",
"versionEndExcluding": "5.15.203",
"versionStartIncluding": "4.16.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "2EDC6BAF-B710-4E26-B6AA-D68922EE7B43",
"versionEndExcluding": "6.1.167",
"versionStartIncluding": "5.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "C57BB918-DF28-46B3-94F7-144176841267",
"versionEndExcluding": "6.6.130",
"versionStartIncluding": "6.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "B3D12E00-E42D-4056-B354-BAD4903C03A5",
"versionEndExcluding": "6.12.77",
"versionStartIncluding": "6.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "A5E006E4-59C7-43C1-9231-62A72219F2BA",
"versionEndExcluding": "6.18.17",
"versionStartIncluding": "6.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "69245D10-0B71-485E-80C3-A64F077004D3",
"versionEndExcluding": "6.19.7",
"versionStartIncluding": "6.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:4.16:-:*:*:*:*:*:*",
"matchCriteriaId": "F60469AF-0A23-41D3-BC6A-C0D9A45A2CBC",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*",
"matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*",
"matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*",
"matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*",
"matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*",
"matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*",
"matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*",
"matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs\n\nWhen shrinking the number of real tx queues,\nnetif_set_real_num_tx_queues() calls qdisc_reset_all_tx_gt() to flush\nqdiscs for queues which will no longer be used.\n\nqdisc_reset_all_tx_gt() currently serializes qdisc_reset() with\nqdisc_lock(). However, for lockless qdiscs, the dequeue path is\nserialized by qdisc_run_begin/end() using qdisc-\u003eseqlock instead, so\nqdisc_reset() can run concurrently with __qdisc_run() and free skbs\nwhile they are still being dequeued, leading to UAF.\n\nThis can easily be reproduced on e.g. virtio-net by imposing heavy\ntraffic while frequently changing the number of queue pairs:\n\n iperf3 -ub0 -c $peer -t 0 \u0026\n while :; do\n ethtool -L eth0 combined 1\n ethtool -L eth0 combined 2\n done\n\nWith KASAN enabled, this leads to reports like:\n\n BUG: KASAN: slab-use-after-free in __qdisc_run+0x133f/0x1760\n ...\n Call Trace:\n \u003cTASK\u003e\n ...\n __qdisc_run+0x133f/0x1760\n __dev_queue_xmit+0x248f/0x3550\n ip_finish_output2+0xa42/0x2110\n ip_output+0x1a7/0x410\n ip_send_skb+0x2e6/0x480\n udp_send_skb+0xb0a/0x1590\n udp_sendmsg+0x13c9/0x1fc0\n ...\n \u003c/TASK\u003e\n\n Allocated by task 1270 on cpu 5 at 44.558414s:\n ...\n alloc_skb_with_frags+0x84/0x7c0\n sock_alloc_send_pskb+0x69a/0x830\n __ip_append_data+0x1b86/0x48c0\n ip_make_skb+0x1e8/0x2b0\n udp_sendmsg+0x13a6/0x1fc0\n ...\n\n Freed by task 1306 on cpu 3 at 44.558445s:\n ...\n kmem_cache_free+0x117/0x5e0\n pfifo_fast_reset+0x14d/0x580\n qdisc_reset+0x9e/0x5f0\n netif_set_real_num_tx_queues+0x303/0x840\n virtnet_set_channels+0x1bf/0x260 [virtio_net]\n ethnl_set_channels+0x684/0xae0\n ethnl_default_set_doit+0x31a/0x890\n ...\n\nSerialize qdisc_reset_all_tx_gt() against the lockless dequeue path by\ntaking qdisc-\u003eseqlock for TCQ_F_NOLOCK qdiscs, matching the\nserialization model already used by dev_reset_queue().\n\nAdditionally clear QDISC_STATE_NON_EMPTY after reset so the qdisc state\nreflects an empty queue, avoiding needless re-scheduling."
},
{
"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad:\n\nnet: sched: evitar la condici\u00f3n de carrera entre qdisc_reset_all_tx_gt() y la eliminaci\u00f3n de la cola para qdiscs sin bloqueo\n\nAl reducir el n\u00famero de colas de transmisi\u00f3n (tx) reales, netif_set_real_num_tx_queues() llama a qdisc_reset_all_tx_gt() para vaciar los qdiscs de las colas que ya no se utilizar\u00e1n.\n\nActualmente, qdisc_reset_all_tx_gt() serializa qdisc_reset() con qdisc_lock(). Sin embargo, para los qdiscs sin bloqueo, la ruta de eliminaci\u00f3n de la cola se serializa mediante qdisc_run_begin/end() usando qdisc-\u0026gt;seqlock en su lugar, por lo que qdisc_reset() puede ejecutarse concurrentemente con __qdisc_run() y liberar skbs mientras a\u00fan se est\u00e1n eliminando de la cola, lo que lleva a un uso despu\u00e9s de liberaci\u00f3n.\n\nEsto se puede reproducir f\u00e1cilmente, por ejemplo, en virtio-net, imponiendo un tr\u00e1fico intenso mientras se cambia frecuentemente el n\u00famero de pares de colas:\n\n iperf3 -ub0 -c $peer -t 0 \u0026amp;\n while :; do\n ethtool -L eth0 combined 1\n ethtool -L eth0 combined 2\n done\n\nCon KASAN habilitado, esto lleva a informes como:\n\n BUG: KASAN: uso despu\u00e9s de liberaci\u00f3n de slab en __qdisc_run+0x133f/0x1760\n ...\n Rastro de Llamada:\n \n ...\n __qdisc_run+0x133f/0x1760\n __dev_queue_xmit+0x248f/0x3550\n ip_finish_output2+0xa42/0x2110\n ip_output+0x1a7/0x410\n ip_send_skb+0x2e6/0x480\n udp_send_skb+0xb0a/0x1590\n udp_sendmsg+0x13c9/0x1fc0\n ...\n \n\n Asignado por la tarea 1270 en la cpu 5 a los 44.558414s:\n ...\n alloc_skb_with_frags+0x84/0x7c0\n sock_alloc_send_pskb+0x69a/0x830\n __ip_append_data+0x1b86/0x48c0\n ip_make_skb+0x1e8/0x2b0\n udp_sendmsg+0x13a6/0x1fc0\n ...\n\n Liberado por la tarea 1306 en la cpu 3 a los 44.558445s:\n ...\n kmem_cache_free+0x117/0x5e0\n pfifo_fast_reset+0x14d/0x580\n qdisc_reset+0x9e/0x5f0\n netif_set_real_num_tx_queues+0x303/0x840\n virtnet_set_channels+0x1bf/0x260 [virtio_net]\n ethnl_set_channels+0x684/0xae0\n ethnl_default_set_doit+0x31a/0x890\n ...\n\nSerializar qdisc_reset_all_tx_gt() contra la ruta de eliminaci\u00f3n de la cola sin bloqueo tomando qdisc-\u0026gt;seqlock para los qdiscs TCQ_F_NOLOCK, coincidiendo con el modelo de serializaci\u00f3n ya utilizado por dev_reset_queue().\n\nAdem\u00e1s, borrar QDISC_STATE_NON_EMPTY despu\u00e9s del reinicio para que el estado del qdisc refleje una cola vac\u00eda, evitando una reprogramaci\u00f3n innecesaria."
}
],
"id": "CVE-2026-23340",
"lastModified": "2026-07-14T13:18:30.280",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-03-25T11:16:31.837",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/5bb27ad54d12de67e457d7d251198e361bef835e"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/5bc4e69306ed7ae02232eb4c0b23ed621a26d504"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/7594467c49bfc2f4644dee0415ac2290db11fa0d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/7f083faf59d14c04e01ec05a7507f036c965acf8"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/8314944cc3bdeaa5a73e6f8a8cf0d94822e625cb"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/c69df4e0524f8de8e176ba389acd83e85f5f49d0"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/dbd58b0730aa06ab6ad26079cf9a5b6b58e7e750"
},
{
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
},
{
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Modified",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-416"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
},
"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-07-02T17:12:34+00:00",
"cve": "CVE-2026-23340",
"id": "CVE-2026-23340",
"initial_release_date": "2026-03-25T00:00:00+00:00",
"product_status:known_affected": "246",
"product_status:known_not_affected": "28",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-23340.json",
"version": "3"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
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.
Loading…
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
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.
Loading…