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GHSA-2H6H-VCRW-57FF

Vulnerability from github – Published: 2024-09-13 06:30 – Updated: 2024-09-13 18:31

Details

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

nfsd: fix potential UAF in nfsd4_cb_getattr_release

Once we drop the delegation reference, the fields embedded in it are no longer safe to access. Do that last.

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-2024-46696"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-09-13T06:15:14Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix potential UAF in nfsd4_cb_getattr_release\n\nOnce we drop the delegation reference, the fields embedded in it are no\nlonger safe to access. Do that last.",
  "id": "GHSA-2h6h-vcrw-57ff",
  "modified": "2024-09-13T18:31:46Z",
  "published": "2024-09-13T06:30:43Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-46696"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1116e0e372eb16dd907ec571ce5d4af325c55c10"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e0b66698a5ae41078f7490e8b3527013f5fccd6c"
    }
  ],
  "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-2024-46696 (GCVE-0-2024-46696)

Vulnerability from cvelistv5 – Published: 2024-09-13 05:29 – Updated: 2026-08-05 11:38

Title

nfsd: fix potential UAF in nfsd4_cb_getattr_release

Summary

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix potential UAF in nfsd4_cb_getattr_release Once we drop the delegation reference, the fields embedded in it are no longer safe to access. Do that last.

Severity

9.8 (Critical)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2024-09-29 15:05 UTC

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/e0b66698a5ae41078…
https://git.kernel.org/stable/c/1116e0e372eb16dd9…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c5967721e1063648b0506481585ba7e2e49a075e , < e0b66698a5ae41078f7490e8b3527013f5fccd6c (git) Affected: c5967721e1063648b0506481585ba7e2e49a075e , < 1116e0e372eb16dd907ec571ce5d4af325c55c10 (git)
Linux	Linux	Affected: 6.9 Unaffected: 0 , < 6.9 (semver) Unaffected: 6.10.8 , ≤ 6.10.* (semver) Unaffected: 6.11 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2024-46696",
                "options": [
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                    "Exploitation": "none"
                  },
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                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-09-29T15:05:32.048367Z",
                "version": "2.0.3"
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        "providerMetadata": {
          "dateUpdated": "2024-09-29T15:05:46.361Z",
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        },
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    "cna": {
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          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs4state.c"
          ],
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          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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              "status": "affected",
              "version": "c5967721e1063648b0506481585ba7e2e49a075e",
              "versionType": "git"
            }
          ]
        },
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          "defaultStatus": "affected",
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          "programFiles": [
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          "versions": [
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              "version": "0",
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              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.11",
              "versionType": "original_commit_for_fix"
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      ],
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          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.11",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix potential UAF in nfsd4_cb_getattr_release\n\nOnce we drop the delegation reference, the fields embedded in it are no\nlonger safe to access. Do that last."
        }
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      "metrics": [
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          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
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              "lang": "en",
              "value": "AV:N - The vulnerable path is in the in-kernel NFS server and is driven entirely by NFSv4 COMPOUND requests (OPEN/GETATTR/DELEGRETURN) and the client\u0027s CB_GETATTR callback reply over TCP port 2049. No local access to the server is needed.\nAC:L - The attacker controls both sides of the race \u2014 the CB_GETATTR reply timing on its own callback channel (the server\u0027s wait is a fixed 30 ms timeout that is trivially exceeded on purpose) and the DELEGRETURN that drops the delegation\u0027s in-force reference \u2014 so it can deterministically arrange for the release callback\u0027s put to be the final one.\nPR:N - NFS AUTH_SYS performs no real authentication: any host permitted by the export list simply asserts a uid, and CVSS does not treat network-level export ACLs as privileges. On a typical rw NFSv4 export the attacker needs only to open a file for write and issue a GETATTR from a second clientid, both pre-any-credential-verification.\nUI:N - The attacker drives both the delegation-holding client and the GETATTR-issuing client itself; no action by any legitimate user or administrator is required.\nS:U - The use-after-free corrupts kernel slab memory within the same security authority as the nfsd server; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - A use-after-free on a freed nfs4_delegation gives the attacker, who can groom the reallocation, read access to the reused object \u2014 the wake path\u0027s test_bit() reads the freed word, and a delegation reused with stale/attacker-adjacent state can leak kernel pointers and file attribute data back over the NFS connection.\nI:H - clear_bit() performs a write into freed slab memory at a fixed offset; since deleg_slab is created with no SLAB_ACCOUNT and no constructor it merges with other same-size caches, turning this into a groomable arbitrary-object bit-clear primitive usable to corrupt flags, counters, or pointer low bits for control-flow hijacking.\nA:H - The use-after-free reliably corrupts freed or reallocated delegation state, causing KASAN-detected UAF, spurious CB_GETATTR re-issue on an in-flight callback, and kernel oops/panic of the NFS file server, which can be triggered repeatedly."
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    "datePublished": "2024-09-13T05:29:24.123Z",
    "dateReserved": "2024-09-11T15:12:18.250Z",
    "dateUpdated": "2026-08-05T11:38:01.015Z",
    "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.

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