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CVE-2026-74267

Estado: RecibidaCrítica (9.8)—

In the Linux kernel, the following vulnerability has been resolved:

net/sched: sch_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen

Whenever 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 codel still has 1 packet on the queue and, thus, will mistakenly deactivate the parent's class causing issues like a wild memory access when qfq has codel as a child:

Leer descripción completaMostrar menos

Fix this by only calling qdisc_tree_reduce_backlog in peek after the qlen is restored.

Detalles técnicos trazas, registros y código del informe original
[   36.339843][  T370] Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI
[   36.340408][  T370] KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127]
[   36.340737][  T370] CPU: 2 UID: 0 PID: 370 Comm: tc Not tainted 7.1.0-rc5-00287-g66e13b626592 #87 PREEMPT(full)
[   36.341113][  T370] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   36.341357][  T370] 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
[   36.342221][  T370] RSP: 0018:ffff8881100ef370 EFLAGS: 00010216
[   36.342422][  T370] RAX: 0000000000000000 RBX: ffff8881058a9568 RCX: dffffc0000000000
[   36.342664][  T370] RDX: 1ffff11021064dc3 RSI: ffff888108326e00 RDI: dffffc0000000000
[   36.342905][  T370] RBP: ffff8881058a8280 R08: dead000000000122 R09: 1bd5a00000000024
[   36.343140][  T370] R10: fffffbfff2940329 R11: fffffbfff2940329 R12: 0000000000000000
[   36.343383][  T370] R13: dead000000000100 R14: ffff8881058a9580 R15: ffff8881058a9578
[   36.343631][  T370] FS:  00007fc04b0ca780(0000) GS:ffff888184fef000(0000) knlGS:0000000000000000
[   36.343911][  T370] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   36.344116][  T370] CR2: 0000557c02c02000 CR3: 000000010e0ba000 CR4: 0000000000750ef0
[   36.344359][  T370] PKRU: 55555554
[   36.344481][  T370] Call Trace:
...
[   36.345054][  T370] qfq_reset_qdisc (net/sched/sch_qfq.c:357 net/sched/sch_qfq.c:1487) sch_qfq
[   36.345222][  T370]  qdisc_reset (net/sched/sch_generic.c:1057)
[   36.345503][  T370]  __qdisc_destroy (net/sched/sch_generic.c:1096)
[   36.345677][  T370]  qdisc_graft (net/sched/sch_api.c:1062 net/sched/sch_api.c:1053 net/sched/sch_api.c:1159)
[   36.346335][  T370]  tc_get_qdisc (net/sched/sch_api.c:1528 net/sched/sch_api.c:1556)

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 de red sin autenticación (AV:N/PR:N/UI:N) en kernel Linux que causa acceso a memoria no canónica y oops/crash. Impacto primario es negación de servicio por corrupción de memoria en el planificador de red (qdisc).

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

Filter Network TrafficVulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkApplication Isolation and Sandboxing

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-74267",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "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": "cc71a757da78dd4aa1b4a9b19cb011833730ccf2",
              "lessThan": "bb9cfd874ee884117b33e92a002b9a45b48202f4",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "eda741fe155ddf5ecd2dd3bfbd4fc3c0c7dbb450",
              "lessThan": "7a05af7f58566682b73578b72ca8e53a268c43bd",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "829c49b6b2ff45b043739168fd1245e4e1a91a30",
              "lessThan": "eba49fd85995a3851c597fa2d214f8d21736e1d8",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "2f9761a94bae33d26e6a81b31b36e7d776d93dc1",
              "lessThan": "e8c6dbadf139cb14ea6ed14add6ed6e88504dedd",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "4d55144b12e742404bb3f8fee6038bafbf45619d",
              "lessThan": "e4615aa6bb7802944ae790cb4b3ef8c1b7491af3",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "342debc12183b51773b3345ba267e9263bdfaaef",
              "lessThan": "755108bb7a5083e911294c416cfea605dc75632f",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "342debc12183b51773b3345ba267e9263bdfaaef",
              "lessThan": "91e0a793a72374c20ab31a40ccec21373e82e973",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "342debc12183b51773b3345ba267e9263bdfaaef",
              "lessThan": "52f1da34c9f4d5bdc1e8b44242da5c7ba8db85f3",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "7a742a9506849d1c1aa71e36c89855ceddc7d58e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e73c838c80dccb9e4f19becc11d9f3cb4a27d483",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a57fe60ef4cf96bfbb6b58397ec28bdb5a5c6b31",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5.10.241",
              "lessThan": "5.10.261",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "5.15.190",
              "lessThan": "5.15.212",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.1.135",
              "lessThan": "6.1.178",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.6.88",
              "lessThan": "6.6.145",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.12.24",
              "lessThan": "6.12.97",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "5.4.297",
              "lessThan": "5.5",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.13.12",
              "lessThan": "6.14",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.14.3",
              "lessThan": "6.15",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "net/sched/sch_codel.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.15",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.261",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/sched/sch_codel.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T06:22:26.030",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/52f1da34c9f4d5bdc1e8b44242da5c7ba8db85f3",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/755108bb7a5083e911294c416cfea605dc75632f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7a05af7f58566682b73578b72ca8e53a268c43bd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/91e0a793a72374c20ab31a40ccec21373e82e973",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/bb9cfd874ee884117b33e92a002b9a45b48202f4",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e4615aa6bb7802944ae790cb4b3ef8c1b7491af3",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e8c6dbadf139cb14ea6ed14add6ed6e88504dedd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/eba49fd85995a3851c597fa2d214f8d21736e1d8",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen\n\nWhenever 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's qlen_notify callback will\nbe executed even though codel still has 1 packet on the queue and, thus,\nwill mistakenly deactivate the parent's class causing issues like a wild\nmemory access when qfq has codel as a child:\n\n[   36.339843][  T370] Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI\n[   36.340408][  T370] KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127]\n[   36.340737][  T370] CPU: 2 UID: 0 PID: 370 Comm: tc Not tainted 7.1.0-rc5-00287-g66e13b626592 #87 PREEMPT(full)\n[   36.341113][  T370] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011\n[   36.341357][  T370] 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[   36.342221][  T370] RSP: 0018:ffff8881100ef370 EFLAGS: 00010216\n[   36.342422][  T370] RAX: 0000000000000000 RBX: ffff8881058a9568 RCX: dffffc0000000000\n[   36.342664][  T370] RDX: 1ffff11021064dc3 RSI: ffff888108326e00 RDI: dffffc0000000000\n[   36.342905][  T370] RBP: ffff8881058a8280 R08: dead000000000122 R09: 1bd5a00000000024\n[   36.343140][  T370] R10: fffffbfff2940329 R11: fffffbfff2940329 R12: 0000000000000000\n[   36.343383][  T370] R13: dead000000000100 R14: ffff8881058a9580 R15: ffff8881058a9578\n[   36.343631][  T370] FS:  00007fc04b0ca780(0000) GS:ffff888184fef000(0000) knlGS:0000000000000000\n[   36.343911][  T370] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[   36.344116][  T370] CR2: 0000557c02c02000 CR3: 000000010e0ba000 CR4: 0000000000750ef0\n[   36.344359][  T370] PKRU: 55555554\n[   36.344481][  T370] Call Trace:\n...\n[   36.345054][  T370] qfq_reset_qdisc (net/sched/sch_qfq.c:357 net/sched/sch_qfq.c:1487) sch_qfq\n[   36.345222][  T370]  qdisc_reset (net/sched/sch_generic.c:1057)\n[   36.345503][  T370]  __qdisc_destroy (net/sched/sch_generic.c:1096)\n[   36.345677][  T370]  qdisc_graft (net/sched/sch_api.c:1062 net/sched/sch_api.c:1053 net/sched/sch_api.c:1159)\n[   36.346335][  T370]  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."
    }
  ],
  "lastModified": "2026-08-17T06:19:20.290",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}