« Volver al listado

CVE-2026-23340

Estado: ModificadaAlta (7.8)—

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.

Leer descripción completaMostrar menos

This can easily be reproduced on e.g. virtio-net by imposing heavy traffic while frequently changing the number of queue pairs:

With KASAN enabled, this leads to reports like:

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.

Detalles técnicos trazas, registros y código del informe original
  iperf3 -ub0 -c $peer -t 0 &
  while :; do
    ethtool -L eth0 combined 1
    ethtool -L eth0 combined 2
  done

  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
   ...

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad local de Use-After-Free (CWE-416) en kernel de Linux que requiere acceso local (AV:L, PR:L) sin interacción del usuario. Permite denegar servicio mediante crash (KASAN UAF) al manipular colas de red, explotable localmente para afectar la disponibilidad del sistema.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Tecnologías afectadas (1)

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-23340",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
              "lessThan": "5bb27ad54d12de67e457d7d251198e361bef835e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
              "lessThan": "7594467c49bfc2f4644dee0415ac2290db11fa0d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
              "lessThan": "dbd58b0730aa06ab6ad26079cf9a5b6b58e7e750",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
              "lessThan": "5bc4e69306ed7ae02232eb4c0b23ed621a26d504",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
              "lessThan": "8314944cc3bdeaa5a73e6f8a8cf0d94822e625cb",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
              "lessThan": "c69df4e0524f8de8e176ba389acd83e85f5f49d0",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7",
              "lessThan": "7f083faf59d14c04e01ec05a7507f036c965acf8",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "include/net/sch_generic.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.16"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "4.16",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.15.203",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.167",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.130",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.77",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.17",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "6.19.7",
              "versionType": "semver",
              "lessThanOrEqual": "6.19.*"
            },
            {
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "include/net/sch_generic.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    },
    {
      "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
      "affectedData": [
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
          "versions": [
            {
              "status": "affected",
              "version": "V3.1.6",
              "lessThan": "*",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
          "versions": [
            {
              "status": "affected",
              "version": "V3.1.5",
              "lessThan": "*",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
          "versions": [
            {
              "status": "affected",
              "version": "V3.1.6",
              "lessThan": "*",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
          "versions": [
            {
              "status": "affected",
              "version": "V3.1.5",
              "lessThan": "*",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
          "versions": [
            {
              "status": "affected",
              "version": "V3.1.6",
              "lessThan": "*",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
          "versions": [
            {
              "status": "affected",
              "version": "V3.1.5",
              "lessThan": "*",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
          "versions": [
            {
              "status": "affected",
              "version": "V3.1.6",
              "lessThan": "*",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
          "versions": [
            {
              "status": "affected",
              "version": "V3.1.5",
              "lessThan": "*",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "vendor": "Siemens",
          "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
          "versions": [
            {
              "status": "affected",
              "version": "V3.1.6",
              "lessThan": "*",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "vendor": "Siemens",
          "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
          "versions": [
            {
              "status": "affected",
              "version": "V3.1.5",
              "lessThan": "*",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        }
      ]
    }
  ],
  "published": "2026-03-25T11:16:31.837",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/5bb27ad54d12de67e457d7d251198e361bef835e",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5bc4e69306ed7ae02232eb4c0b23ed621a26d504",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7594467c49bfc2f4644dee0415ac2290db11fa0d",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7f083faf59d14c04e01ec05a7507f036c965acf8",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8314944cc3bdeaa5a73e6f8a8cf0d94822e625cb",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c69df4e0524f8de8e176ba389acd83e85f5f49d0",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/dbd58b0730aa06ab6ad26079cf9a5b6b58e7e750",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "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",
      "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    }
  ],
  "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->seqlock 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 &\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   <TASK>\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   </TASK>\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->seqlock 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 condición de carrera entre qdisc_reset_all_tx_gt() y la eliminación de la cola para qdiscs sin bloqueo\n\nAl reducir el número de colas de transmisión (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 utilizarán.\n\nActualmente, qdisc_reset_all_tx_gt() serializa qdisc_reset() con qdisc_lock(). Sin embargo, para los qdiscs sin bloqueo, la ruta de eliminación de la cola se serializa mediante qdisc_run_begin/end() usando qdisc-&gt;seqlock en su lugar, por lo que qdisc_reset() puede ejecutarse concurrentemente con __qdisc_run() y liberar skbs mientras aún se están eliminando de la cola, lo que lleva a un uso después de liberación.\n\nEsto se puede reproducir fácilmente, por ejemplo, en virtio-net, imponiendo un tráfico intenso mientras se cambia frecuentemente el número de pares de colas:\n\n  iperf3 -ub0 -c $peer -t 0 &amp;\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 después de liberación 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 eliminación de la cola sin bloqueo tomando qdisc-&gt;seqlock para los qdiscs TCQ_F_NOLOCK, coincidiendo con el modelo de serialización ya utilizado por dev_reset_queue().\n\nAdemás, borrar QDISC_STATE_NON_EMPTY después del reinicio para que el estado del qdisc refleje una cola vacía, evitando una reprogramación innecesaria."
    }
  ],
  "lastModified": "2026-07-14T13:18:30.280",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "2084F3CA-9155-4C25-AE7F-A6BC24B53E24",
              "versionEndExcluding": "5.15.203",
              "versionStartIncluding": "4.16.1"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "2EDC6BAF-B710-4E26-B6AA-D68922EE7B43",
              "versionEndExcluding": "6.1.167",
              "versionStartIncluding": "5.16"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "C57BB918-DF28-46B3-94F7-144176841267",
              "versionEndExcluding": "6.6.130",
              "versionStartIncluding": "6.2"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "B3D12E00-E42D-4056-B354-BAD4903C03A5",
              "versionEndExcluding": "6.12.77",
              "versionStartIncluding": "6.7"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "A5E006E4-59C7-43C1-9231-62A72219F2BA",
              "versionEndExcluding": "6.18.17",
              "versionStartIncluding": "6.13"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "69245D10-0B71-485E-80C3-A64F077004D3",
              "versionEndExcluding": "6.19.7",
              "versionStartIncluding": "6.19"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:4.16:-:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F60469AF-0A23-41D3-BC6A-C0D9A45A2CBC"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}