Vulnerability-Lookup

GHSA-QC77-246G-GJ7G

Vulnerability from github – Published: 2026-06-24 18:32 – Updated: 2026-06-24 18:32

Details

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.

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.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-52997"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-24T17:17:10Z",
    "severity": null
  },
  "details": "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.",
  "id": "GHSA-qc77-246g-gj7g",
  "modified": "2026-06-24T18:32:43Z",
  "published": "2026-06-24T18:32:43Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52997"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3042add80c2c50bd127d570b83319af612efde65"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/478ed6b7d2577439c610f91fa8759a4c878a4264"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/86cf2eba2056bcf9c41fba260e599bd95bf9943b"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-52997 (GCVE-0-2026-52997)

Vulnerability from cvelistv5 – Published: 2026-06-24 16:29 – Updated: 2026-06-24 16:29

Title

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

Summary

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. 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.

Severity

No CVSS data available.

Assigner

Linux

References

3 references

URL	Tags
https://git.kernel.org/stable/c/86cf2eba2056bcf9c…
https://git.kernel.org/stable/c/3042add80c2c50bd1…
https://git.kernel.org/stable/c/478ed6b7d2577439c…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 320d031ad6e4d67e8e1ab08ac71efda02bc85683 , < 86cf2eba2056bcf9c41fba260e599bd95bf9943b (git) Affected: 320d031ad6e4d67e8e1ab08ac71efda02bc85683 , < 3042add80c2c50bd127d570b83319af612efde65 (git) Affected: 320d031ad6e4d67e8e1ab08ac71efda02bc85683 , < 478ed6b7d2577439c610f91fa8759a4c878a4264 (git)
Linux	Linux	Affected: 6.17 Unaffected: 0 , < 6.17 (semver) Unaffected: 6.18.33 , ≤ 6.18.* (semver) Unaffected: 7.0.10 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_dualpi2.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "86cf2eba2056bcf9c41fba260e599bd95bf9943b",
              "status": "affected",
              "version": "320d031ad6e4d67e8e1ab08ac71efda02bc85683",
              "versionType": "git"
            },
            {
              "lessThan": "3042add80c2c50bd127d570b83319af612efde65",
              "status": "affected",
              "version": "320d031ad6e4d67e8e1ab08ac71efda02bc85683",
              "versionType": "git"
            },
            {
              "lessThan": "478ed6b7d2577439c610f91fa8759a4c878a4264",
              "status": "affected",
              "version": "320d031ad6e4d67e8e1ab08ac71efda02bc85683",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_dualpi2.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.17"
            },
            {
              "lessThan": "6.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.33",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.33",
                  "versionStartIncluding": "6.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "6.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.17",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-24T16:29:09.997Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/3042add80c2c50bd127d570b83319af612efde65"
        },
        {
          "url": "https://git.kernel.org/stable/c/478ed6b7d2577439c610f91fa8759a4c878a4264"
        }
      ],
      "title": "net/sched: sch_dualpi2: drain both C-queue and L-queue in dualpi2_change()",
      "x_generator": {
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-52997",
    "datePublished": "2026-06-24T16:29:09.997Z",
    "dateReserved": "2026-06-09T07:44:35.377Z",
    "dateUpdated": "2026-06-24T16:29:09.997Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-QC77-246G-GJ7G

CVE-2026-52997 (GCVE-0-2026-52997)

Tags

Sightings

Nomenclature