Vulnerability-Lookup

FKIE_CVE-2026-22999

Vulnerability from fkie_nvd - Published: 2026-01-25 15:15 - Updated: 2026-06-17 13:20

Severity

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_qfq: do not free existing class in qfq_change_class() Fixes qfq_change_class() error case. cl->qdisc and cl should only be freed if a new class and qdisc were allocated, or we risk various UAF.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/0a234660dc70ce45d771cbc76b20d925b73ec160	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2a64fb9b47afffeb5dbab5fd3a518e1436dcc90e	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/362e269bb03f7076ba9990e518aeddb898232e50	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/3879cffd9d07aa0377c4b8835c4f64b4fb24ac78	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/cff6cd703f41d8071995956142729e4bba160363	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/e9d8f11652fa08c647bf7bba7dd8163241a332cd	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/f06f7635499bc806cbe2bbc8805c7cef8b1edddf	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	6.19
linux	linux_kernel	6.19
linux	linux_kernel	6.19
linux	linux_kernel	6.19
linux	linux_kernel	6.19

JSON

To clipboard

{
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    },
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    }
  ],
  "id": "CVE-2026-22999",
  "lastModified": "2026-06-17T13:20:10.273",
  "metrics": {
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          "attackComplexity": "LOW",
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}

CVE-2026-22999 (GCVE-0-2026-22999)

Vulnerability from cvelistv5 – Published: 2026-01-25 14:36 – Updated: 2026-08-05 12:20

Title

net/sched: sch_qfq: do not free existing class in qfq_change_class()

Summary

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-16 20:35 UTC

Assigner

Linux mitre root Scorecard

References

7 references

URL	Tags
https://git.kernel.org/stable/c/2a64fb9b47afffeb5…
https://git.kernel.org/stable/c/cff6cd703f41d8071…
https://git.kernel.org/stable/c/f06f7635499bc806c…
https://git.kernel.org/stable/c/0a234660dc70ce45d…
https://git.kernel.org/stable/c/362e269bb03f7076b…
https://git.kernel.org/stable/c/e9d8f11652fa08c64…
https://git.kernel.org/stable/c/3879cffd9d07aa037…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 462dbc9101acd38e92eda93c0726857517a24bbd , < 2a64fb9b47afffeb5dbab5fd3a518e1436dcc90e (git) Affected: 462dbc9101acd38e92eda93c0726857517a24bbd , < cff6cd703f41d8071995956142729e4bba160363 (git) Affected: 462dbc9101acd38e92eda93c0726857517a24bbd , < f06f7635499bc806cbe2bbc8805c7cef8b1edddf (git) Affected: 462dbc9101acd38e92eda93c0726857517a24bbd , < 0a234660dc70ce45d771cbc76b20d925b73ec160 (git) Affected: 462dbc9101acd38e92eda93c0726857517a24bbd , < 362e269bb03f7076ba9990e518aeddb898232e50 (git) Affected: 462dbc9101acd38e92eda93c0726857517a24bbd , < e9d8f11652fa08c647bf7bba7dd8163241a332cd (git) Affected: 462dbc9101acd38e92eda93c0726857517a24bbd , < 3879cffd9d07aa0377c4b8835c4f64b4fb24ac78 (git)
Linux	Linux	Affected: 3.8 Unaffected: 0 , < 3.8 (semver) Unaffected: 5.10.249 , ≤ 5.10.* (semver) Unaffected: 5.15.199 , ≤ 5.15.* (semver) Unaffected: 6.1.162 , ≤ 6.1.* (semver) Unaffected: 6.6.122 , ≤ 6.6.* (semver) Unaffected: 6.12.67 , ≤ 6.12.* (semver) Unaffected: 6.18.7 , ≤ 6.18.* (semver) Unaffected: 6.19 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
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      {
        "metrics": [
          {
            "other": {
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                "id": "CVE-2026-22999",
                "options": [
                  {
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                  },
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                  },
                  {
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                "timestamp": "2026-06-16T20:35:55.025194Z",
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.122",
                  "versionStartIncluding": "3.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.67",
                  "versionStartIncluding": "3.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.7",
                  "versionStartIncluding": "3.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19",
                  "versionStartIncluding": "3.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_qfq: do not free existing class in qfq_change_class()\n\nFixes qfq_change_class() error case.\n\ncl-\u003eqdisc and cl should only be freed if a new class and qdisc\nwere allocated, or we risk various UAF."
        }
      ],
      "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 - The vulnerable `qfq_change_class()` path is reached through local rtnetlink/tc `RTM_NEWTCLASS` messages, ultimately sent via a netlink socket from userspace. It is not reachable directly from remote network packets.\nAC:L - The attacker controls the qdisc/class setup and can repeatedly attempt the class-change error path; there is no victim race or external timing requirement. Although the observed bad path depends on allocation failure, local memory pressure/failure conditions are attacker-influenceable, and uncertainty is scored upward.\nPR:L - Rtnetlink rejects non-GET tc operations without `CAP_NET_ADMIN` in the relevant network namespace. Because tc/qdisc operations are reachable inside user-created network namespaces on systems allowing unprivileged user namespaces, this is low privilege rather than real init-namespace root.\nUI:N - No victim action is required after the attacker has local execution and sends crafted netlink messages. The trigger is entirely attacker-driven.\nS:U - The impact is within the kernel/local host security authority. This is not a VM escape, IOMMU bypass, or cross-authority boundary violation.\nC:H - The bug frees an existing `struct qfq_class` while it remains reachable from the qdisc class hash and scheduler paths, creating a kernel heap use-after-free. Reclaiming the kmalloc-128 object can turn later class dumps/searches/pointer dereferences into strong information disclosure primitives.\nI:H - The stale class contains pointers such as `qdisc`, `agg`, list/hash nodes, and stats fields that are later read and modified by enqueue/dequeue, graft, dump, reset, and destroy paths. A controllable UAF in these scheduler structures is defensibly exploitable for kernel memory corruption or control-flow/data integrity compromise.\nA:H - The public syzbot report demonstrates a KASAN slab-use-after-free in `qfq_search_class`, and the stale object is also used by multiple qdisc paths. Even without full exploitation, this can cause kernel oops/panic or persistent scheduler corruption."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:20:03.450Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2a64fb9b47afffeb5dbab5fd3a518e1436dcc90e"
        },
        {
          "url": "https://git.kernel.org/stable/c/cff6cd703f41d8071995956142729e4bba160363"
        },
        {
          "url": "https://git.kernel.org/stable/c/f06f7635499bc806cbe2bbc8805c7cef8b1edddf"
        },
        {
          "url": "https://git.kernel.org/stable/c/0a234660dc70ce45d771cbc76b20d925b73ec160"
        },
        {
          "url": "https://git.kernel.org/stable/c/362e269bb03f7076ba9990e518aeddb898232e50"
        },
        {
          "url": "https://git.kernel.org/stable/c/e9d8f11652fa08c647bf7bba7dd8163241a332cd"
        },
        {
          "url": "https://git.kernel.org/stable/c/3879cffd9d07aa0377c4b8835c4f64b4fb24ac78"
        }
      ],
      "title": "net/sched: sch_qfq: do not free existing class in qfq_change_class()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-22999",
    "datePublished": "2026-01-25T14:36:13.909Z",
    "dateReserved": "2026-01-13T15:37:45.938Z",
    "dateUpdated": "2026-08-05T12:20:03.450Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

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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.
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FKIE_CVE-2026-22999

CVE-2026-22999 (GCVE-0-2026-22999)

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