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CVE-2026-52997

Estado: AnalizadaMedia (5.5)—

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

net/sched: sch_dualpi2: drain both C-queue and L-queue in dualpi2_change()

Fix dualpi2_change() to correctly enforce updated limit and memlimit values after a configuration change of the dualpi2 qdisc.

Before this patch, dualpi2_change() always attempted to dequeue packets via the root qdisc (C-queue) when reducing backlog or memory usage, and unconditionally assumed that a valid skb will be returned. When traffic classification results in packets being queued in the L-queue while the C-queue is empty, this leads to a NULL skb dereference during limit or memlimit enforcement.

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This is fixed by first dequeuing from the C-queue path if it is non-empty. Once the C-queue is empty, packets are dequeued directly from the L-queue. Return values from qdisc_dequeue_internal() are checked for both queues. When dequeuing from the L-queue, the parent qdisc qlen and backlog counters are updated explicitly to keep overall qdisc statistics consistent.

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).

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-52997",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
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      "affectedData": [
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
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            },
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              "versionType": "semver"
            },
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              "versionType": "original_commit_for_fix",
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            }
          ],
          "programFiles": [
            "net/sched/sch_dualpi2.c"
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          "defaultStatus": "affected"
        }
      ]
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  ],
  "published": "2026-06-24T17:17:10.680",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/3042add80c2c50bd127d570b83319af612efde65",
      "tags": [
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
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      "tags": [
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      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_dualpi2: drain both C-queue and L-queue in dualpi2_change()\n\nFix dualpi2_change() to correctly enforce updated limit and memlimit\nvalues after a configuration change of the dualpi2 qdisc.\n\nBefore this patch, dualpi2_change() always attempted to dequeue packets\nvia the root qdisc (C-queue) when reducing backlog or memory usage, and\nunconditionally assumed that a valid skb will be returned. When traffic\nclassification results in packets being queued in the L-queue while the\nC-queue is empty, this leads to a NULL skb dereference during limit or\nmemlimit enforcement.\n\nThis is fixed by first dequeuing from the C-queue path if it is\nnon-empty. Once the C-queue is empty, packets are dequeued directly from\nthe L-queue. Return values from qdisc_dequeue_internal() are checked for\nboth queues. When dequeuing from the L-queue, the parent qdisc qlen and\nbacklog counters are updated explicitly to keep overall qdisc statistics\nconsistent."
    }
  ],
  "lastModified": "2026-07-15T12:56:38.053",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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              "matchCriteriaId": "4F0E1027-1081-4E2B-9D56-AF79BAFF146B",
              "versionEndExcluding": "6.18.33",
              "versionStartIncluding": "6.17"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "A13475D2-59BF-4716-94B5-7C1D239A2CF4",
              "versionEndExcluding": "7.0.10",
              "versionStartIncluding": "6.19"
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          ],
          "operator": "OR"
        }
      ]
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  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}