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GHSA-G6HQ-4292-HHWX

Vulnerability from github – Published: 2026-05-08 15:31 – Updated: 2026-05-11 09:30

Details

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

io_uring/kbuf: check if target buffer list is still legacy on recycle

There's a gap between when the buffer was grabbed and when it potentially gets recycled, where if the list is empty, someone could've upgraded it to a ring provided type. This can happen if the request is forced via io-wq. The legacy recycling is missing checking if the buffer_list still exists, and if it's of the correct type. Add those checks.

Severity

7.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-43366"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-08T15:16:47Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/kbuf: check if target buffer list is still legacy on recycle\n\nThere\u0027s a gap between when the buffer was grabbed and when it\npotentially gets recycled, where if the list is empty, someone could\u0027ve\nupgraded it to a ring provided type. This can happen if the request\nis forced via io-wq. The legacy recycling is missing checking if the\nbuffer_list still exists, and if it\u0027s of the correct type. Add those\nchecks.",
  "id": "GHSA-g6hq-4292-hhwx",
  "modified": "2026-05-11T09:30:30Z",
  "published": "2026-05-08T15:31:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43366"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/439a6728ec4641ffad1ca796622c19bc525e570f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/50ad880db3013c6fee0ef13781762a39e2e7ef83"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/97b57f69fee1b61b41acbf37e7720cac9d389fa4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a7b33671e418fca507feebd1d56e7f4952a4b25c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c2c185be5c85d37215397c8e8781abf0a69bec1f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-43366 (GCVE-0-2026-43366)

Vulnerability from cvelistv5 – Published: 2026-05-08 14:21 – Updated: 2026-08-05 12:27

Title

io_uring/kbuf: check if target buffer list is still legacy on recycle

Summary

In the Linux kernel, the following vulnerability has been resolved: io_uring/kbuf: check if target buffer list is still legacy on recycle There's a gap between when the buffer was grabbed and when it potentially gets recycled, where if the list is empty, someone could've upgraded it to a ring provided type. This can happen if the request is forced via io-wq. The legacy recycling is missing checking if the buffer_list still exists, and if it's of the correct type. Add those checks.

Severity

7.8 (High)


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

Assigner

Linux mitre root Scorecard

References

6 references

URL	Tags
https://git.kernel.org/stable/c/a7b33671e418fca50…
https://git.kernel.org/stable/c/439a6728ec4641ffa…
https://git.kernel.org/stable/c/f3fb54e7a8b4aadcc…
https://git.kernel.org/stable/c/50ad880db3013c6fe…
https://git.kernel.org/stable/c/97b57f69fee1b61b4…
https://git.kernel.org/stable/c/c2c185be5c85d3721…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c7fb19428d67dd0a2a78a4f237af01d39c78dc5a , < a7b33671e418fca507feebd1d56e7f4952a4b25c (git) Affected: c7fb19428d67dd0a2a78a4f237af01d39c78dc5a , < 439a6728ec4641ffad1ca796622c19bc525e570f (git) Affected: c7fb19428d67dd0a2a78a4f237af01d39c78dc5a , < f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa (git) Affected: c7fb19428d67dd0a2a78a4f237af01d39c78dc5a , < 50ad880db3013c6fee0ef13781762a39e2e7ef83 (git) Affected: c7fb19428d67dd0a2a78a4f237af01d39c78dc5a , < 97b57f69fee1b61b41acbf37e7720cac9d389fa4 (git) Affected: c7fb19428d67dd0a2a78a4f237af01d39c78dc5a , < c2c185be5c85d37215397c8e8781abf0a69bec1f (git)
Linux	Linux	Affected: 5.19 Unaffected: 0 , < 5.19 (semver) Unaffected: 6.1.167 , ≤ 6.1.* (semver) Unaffected: 6.6.130 , ≤ 6.6.* (semver) Unaffected: 6.12.78 , ≤ 6.12.* (semver) Unaffected: 6.18.19 , ≤ 6.18.* (semver) Unaffected: 6.19.9 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "io_uring/kbuf.c"
          ],
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          "vendor": "Linux",
          "versions": [
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              "version": "c7fb19428d67dd0a2a78a4f237af01d39c78dc5a",
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              "versionType": "git"
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              "status": "affected",
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              "versionType": "git"
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              "version": "0",
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              "versionType": "semver"
            },
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              "status": "unaffected",
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            },
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              "versionType": "semver"
            },
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              "versionType": "semver"
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "5.19",
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/kbuf: check if target buffer list is still legacy on recycle\n\nThere\u0027s a gap between when the buffer was grabbed and when it\npotentially gets recycled, where if the list is empty, someone could\u0027ve\nupgraded it to a ring provided type. This can happen if the request\nis forced via io-wq. The legacy recycling is missing checking if the\nbuffer_list still exists, and if it\u0027s of the correct type. Add those\nchecks."
        }
      ],
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        {
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            "baseSeverity": "HIGH",
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              "value": "AV:L - The vulnerable code is reachable through local `io_uring_setup`, `io_uring_enter`, and `io_uring_register` operations using provided buffer selection and buffer-ring registration. It is not directly reachable from network packets or physical/adjacent interfaces.\nAC:L - The attacker controls the io_uring ring, the legacy provided buffer group, the in-flight async/io-wq request, and the conversion/removal of the same buffer group. The required timing can be driven by attacker-controlled concurrent local operations, so the race/lifecycle window is low complexity.\nPR:L - Exploitation requires a local unprivileged user able to create and use an io_uring instance; the relevant setup/register/submit paths do not require real root or init-namespace capabilities when io_uring is enabled. This is basic local user privilege, not administrator privilege.\nUI:N - No victim action is required after the attacker runs local code. The attacker performs all setup, submission, and buffer group conversion operations directly.\nS:U - The bug corrupts kernel memory from within the kernel/io_uring security authority and can lead to local kernel compromise or crash. It does not inherently cross a VM, IOMMU, or separate authorization boundary.\nC:H - The legacy recycle path can type-confuse a ring-provided buffer list and write kernel pointers into attacker-observable ring memory, and subsequent use can treat attacker-influenced objects as buffer-ring state. This is kernel memory corruption with a defensible path to high confidentiality impact.\nI:H - Recycling a legacy `struct io_buffer` into a ring buffer list corrupts list/ring state and can turn later ring-buffer operations into controlled kernel memory misuse. As a type confusion/memory corruption bug, high integrity impact is appropriate.\nA:H - If the target buffer list has been removed the old code can dereference a NULL buffer-list pointer, and if it has been upgraded it corrupts kernel state. Either case can produce an oops/panic or otherwise destabilize the kernel."
            }
          ]
        }
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        "dateUpdated": "2026-08-05T12:27:30.302Z",
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    "cveId": "CVE-2026-43366",
    "datePublished": "2026-05-08T14:21:19.191Z",
    "dateReserved": "2026-05-01T14:12:56.005Z",
    "dateUpdated": "2026-08-05T12:27:30.302Z",
    "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.

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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GHSA-G6HQ-4292-HHWX

CVE-2026-43366 (GCVE-0-2026-43366)

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