Vulnerability-Lookup

GHSA-W44C-CV6C-X94C

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-11 21:31

Details

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

io_uring/query: cap user size passed to copy_struct_to_user

io_handle_query_entry() clamps hdr.size for the inbound copy_from_user() but keeps the original user value as usize. copy_struct_to_user() uses that usize and, when it is larger than the kernel result, clear_user()s the trailing bytes.

As hdr.size is a __u32, a query can request nearly 4 GiB of zeroing, including on the error path where res_size stays 0. The interface is reachable without a ring via IORING_REGISTER_QUERY.

Reject sizes larger than PAGE_SIZE, as recommended for copy_struct_* interfaces.

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-81009"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:09Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/query: cap user size passed to copy_struct_to_user\n\nio_handle_query_entry() clamps hdr.size for the inbound copy_from_user()\nbut keeps the original user value as usize. copy_struct_to_user() uses\nthat usize and, when it is larger than the kernel result, clear_user()s\nthe trailing bytes.\n\nAs hdr.size is a __u32, a query can request nearly 4 GiB of zeroing,\nincluding on the error path where res_size stays 0. The interface is\nreachable without a ring via IORING_REGISTER_QUERY.\n\nReject sizes larger than PAGE_SIZE, as recommended for copy_struct_*\ninterfaces.",
  "id": "GHSA-w44c-cv6c-x94c",
  "modified": "2026-09-11T21:31:24Z",
  "published": "2026-09-11T21:31:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-81009"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2b8ad4981ecedb14c1fdd811ab977010b23933e6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/417e02f7b6051765b91cf1289071882eebd172e0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ba77efee1b95b4ad7559b1cdbe7cd7fa36dca95b"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-81009 (GCVE-0-2026-81009)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:43 – Updated: 2026-09-11 19:43

Title

io_uring/query: cap user size passed to copy_struct_to_user

Summary

In the Linux kernel, the following vulnerability has been resolved: io_uring/query: cap user size passed to copy_struct_to_user io_handle_query_entry() clamps hdr.size for the inbound copy_from_user() but keeps the original user value as usize. copy_struct_to_user() uses that usize and, when it is larger than the kernel result, clear_user()s the trailing bytes. As hdr.size is a __u32, a query can request nearly 4 GiB of zeroing, including on the error path where res_size stays 0. The interface is reachable without a ring via IORING_REGISTER_QUERY. Reject sizes larger than PAGE_SIZE, as recommended for copy_struct_* interfaces.

Severity

No CVSS data available.

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/417e02f7b6051765b…
https://git.kernel.org/stable/c/2b8ad4981ecedb14c…
https://git.kernel.org/stable/c/ba77efee1b95b4ad7…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c265ae75f900cea4e415230a77b5d152377627dd , < 417e02f7b6051765b91cf1289071882eebd172e0 (git) Affected: c265ae75f900cea4e415230a77b5d152377627dd , < 2b8ad4981ecedb14c1fdd811ab977010b23933e6 (git) Affected: c265ae75f900cea4e415230a77b5d152377627dd , < ba77efee1b95b4ad7559b1cdbe7cd7fa36dca95b (git)
Linux	Linux	Affected: 6.18 Unaffected: 0 , < 6.18 (semver) Unaffected: 6.18.50 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "io_uring/query.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "417e02f7b6051765b91cf1289071882eebd172e0",
              "status": "affected",
              "version": "c265ae75f900cea4e415230a77b5d152377627dd",
              "versionType": "git"
            },
            {
              "lessThan": "2b8ad4981ecedb14c1fdd811ab977010b23933e6",
              "status": "affected",
              "version": "c265ae75f900cea4e415230a77b5d152377627dd",
              "versionType": "git"
            },
            {
              "lessThan": "ba77efee1b95b4ad7559b1cdbe7cd7fa36dca95b",
              "status": "affected",
              "version": "c265ae75f900cea4e415230a77b5d152377627dd",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "io_uring/query.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/query: cap user size passed to copy_struct_to_user\n\nio_handle_query_entry() clamps hdr.size for the inbound copy_from_user()\nbut keeps the original user value as usize. copy_struct_to_user() uses\nthat usize and, when it is larger than the kernel result, clear_user()s\nthe trailing bytes.\n\nAs hdr.size is a __u32, a query can request nearly 4 GiB of zeroing,\nincluding on the error path where res_size stays 0. The interface is\nreachable without a ring via IORING_REGISTER_QUERY.\n\nReject sizes larger than PAGE_SIZE, as recommended for copy_struct_*\ninterfaces."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-11T19:43:00.074Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/417e02f7b6051765b91cf1289071882eebd172e0"
        },
        {
          "url": "https://git.kernel.org/stable/c/2b8ad4981ecedb14c1fdd811ab977010b23933e6"
        },
        {
          "url": "https://git.kernel.org/stable/c/ba77efee1b95b4ad7559b1cdbe7cd7fa36dca95b"
        }
      ],
      "title": "io_uring/query: cap user size passed to copy_struct_to_user",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-81009",
    "datePublished": "2026-09-11T19:43:00.074Z",
    "dateReserved": "2026-08-26T14:34:25.812Z",
    "dateUpdated": "2026-09-11T19:43:00.074Z",
    "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.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.