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GHSA-5968-J93G-C79F

Vulnerability from github – Published: 2026-06-24 18:32 – Updated: 2026-06-28 09:31

Details

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

NFSD: fix nfs4_file access extra count in nfsd4_add_rdaccess_to_wrdeleg

In nfsd4_add_rdaccess_to_wrdeleg, if fp->fi_fds[O_RDONLY] is already set by another thread, __nfs4_file_get_access should not be called to increment the nfs4_file access count since that was already done by the thread that added READ access to the file. The extra fi_access count in nfs4_file can prevent the corresponding nfsd_file from being freed.

When stopping nfs-server service, these extra access counts trigger a BUG in kmem_cache_destroy() that shows nfsd_file object remaining on __kmem_cache_shutdown.

This problem can be reproduced by running the Git project's test suite over NFS.

Severity

7.5 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-53026"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-24T17:17:13Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: fix nfs4_file access extra count in nfsd4_add_rdaccess_to_wrdeleg\n\nIn nfsd4_add_rdaccess_to_wrdeleg, if fp-\u003efi_fds[O_RDONLY] is already\nset by another thread, __nfs4_file_get_access should not be called\nto increment the nfs4_file access count since that was already done\nby the thread that added READ access to the file. The extra fi_access\ncount in nfs4_file can prevent the corresponding nfsd_file from being\nfreed.\n\nWhen stopping nfs-server service, these extra access counts trigger a\nBUG in kmem_cache_destroy() that shows nfsd_file object remaining on\n__kmem_cache_shutdown.\n\nThis problem can be reproduced by running the Git project\u0027s test\nsuite over NFS.",
  "id": "GHSA-5968-j93g-c79f",
  "modified": "2026-06-28T09:31:39Z",
  "published": "2026-06-24T18:32:44Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53026"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4584229395d0d65bd517780afe97ffea07cb2c3d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b48f44f36e6607b2f818560f19deb86b4a9c717b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b81572b073441dfd32213e41857676d0dbff4665"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-53026 (GCVE-0-2026-53026)

Vulnerability from cvelistv5 – Published: 2026-06-24 16:29 – Updated: 2026-08-05 12:32

Title

NFSD: fix nfs4_file access extra count in nfsd4_add_rdaccess_to_wrdeleg

Summary

In the Linux kernel, the following vulnerability has been resolved: NFSD: fix nfs4_file access extra count in nfsd4_add_rdaccess_to_wrdeleg In nfsd4_add_rdaccess_to_wrdeleg, if fp->fi_fds[O_RDONLY] is already set by another thread, __nfs4_file_get_access should not be called to increment the nfs4_file access count since that was already done by the thread that added READ access to the file. The extra fi_access count in nfs4_file can prevent the corresponding nfsd_file from being freed. When stopping nfs-server service, these extra access counts trigger a BUG in kmem_cache_destroy() that shows nfsd_file object remaining on __kmem_cache_shutdown. This problem can be reproduced by running the Git project's test suite over NFS.

Severity

7.5 (High)


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

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/4584229395d0d65bd…
https://git.kernel.org/stable/c/b81572b073441dfd3…
https://git.kernel.org/stable/c/b48f44f36e6607b2f…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c07dc84ed67c5a182273171639bacbbb87c12175 , < 4584229395d0d65bd517780afe97ffea07cb2c3d (git) Affected: 8072e34e1387d03102b788677d491e2bcceef6f5 , < b81572b073441dfd32213e41857676d0dbff4665 (git) Affected: 8072e34e1387d03102b788677d491e2bcceef6f5 , < b48f44f36e6607b2f818560f19deb86b4a9c717b (git) Affected: 6.18.4 , < 6.18.33 (semver)
Linux	Linux	Affected: 6.19 Unaffected: 0 , < 6.19 (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": [
            "fs/nfsd/nfs4state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "b81572b073441dfd32213e41857676d0dbff4665",
              "status": "affected",
              "version": "8072e34e1387d03102b788677d491e2bcceef6f5",
              "versionType": "git"
            },
            {
              "lessThan": "b48f44f36e6607b2f818560f19deb86b4a9c717b",
              "status": "affected",
              "version": "8072e34e1387d03102b788677d491e2bcceef6f5",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "6.18.4",
              "versionType": "semver"
            }
          ]
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          "product": "Linux",
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            "fs/nfsd/nfs4state.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.19"
            },
            {
              "lessThan": "6.19",
              "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"
            }
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        }
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      "cpeApplicability": [
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          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.33",
                  "versionStartIncluding": "6.18.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.10",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                }
              ],
              "negate": false,
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            }
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: fix nfs4_file access extra count in nfsd4_add_rdaccess_to_wrdeleg\n\nIn nfsd4_add_rdaccess_to_wrdeleg, if fp-\u003efi_fds[O_RDONLY] is already\nset by another thread, __nfs4_file_get_access should not be called\nto increment the nfs4_file access count since that was already done\nby the thread that added READ access to the file. The extra fi_access\ncount in nfs4_file can prevent the corresponding nfsd_file from being\nfreed.\n\nWhen stopping nfs-server service, these extra access counts trigger a\nBUG in kmem_cache_destroy() that shows nfsd_file object remaining on\n__kmem_cache_shutdown.\n\nThis problem can be reproduced by running the Git project\u0027s test\nsuite over NFS."
        }
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            "baseSeverity": "HIGH",
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            "version": "3.1"
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          "scenarios": [
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              "value": "AV:N - NFSD is a network-facing NFS server subsystem, and the vulnerable path is reached by remote NFSv4 COMPOUND/OPEN requests over RPC.\nAC:L - A client can drive repeated or concurrent OPEN/write-delegation activity against an exported file; the relevant race/refcount condition is controllable by issuing parallel NFS requests.\nPR:N - In a reasonable NFS deployment using AUTH_SYS/AUTH_NULL-accessible exports, a remote client can reach this path without authenticated target-system privileges.\nUI:N - No victim user action is required; the attacker only sends NFS requests to the server.\nS:U - The impact remains within the vulnerable kernel/NFSD server security authority and does not cross a VM, sandbox, or other separate security boundary.\nC:N - The bug is an extra reference/access count leak, not a use-after-free, out-of-bounds access, or information disclosure primitive.\nI:N - The investigation found no attacker-controlled memory overwrite or data modification primitive; the corruption is limited to over-retaining an internal reference count.\nA:H - The leaked access counts can keep nfsd_file objects pinned and trigger a kmem_cache_destroy BUG during NFSD shutdown; repeated triggering can deny service through persistent kernel resource leakage."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:32:44.026Z",
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        {
          "url": "https://git.kernel.org/stable/c/b48f44f36e6607b2f818560f19deb86b4a9c717b"
        }
      ],
      "title": "NFSD: fix nfs4_file access extra count in nfsd4_add_rdaccess_to_wrdeleg",
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        "engine": "bippy-1.2.0"
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    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-53026",
    "datePublished": "2026-06-24T16:29:34.855Z",
    "dateReserved": "2026-06-09T07:44:35.379Z",
    "dateUpdated": "2026-08-05T12:32:44.026Z",
    "state": "PUBLISHED"
  },
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  "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.
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