CVE-2026-53026 (GCVE-0-2026-53026)
Vulnerability from cvelistv5
Published
2026-06-24 16:29
Modified
2026-08-05 12:32
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: c07dc84ed67c5a182273171639bacbbb87c12175
Version: 8072e34e1387d03102b788677d491e2bcceef6f5
Version: 8072e34e1387d03102b788677d491e2bcceef6f5
Version: 6.18.4   ≤
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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",
          "versions": [
            {
              "lessThan": "4584229395d0d65bd517780afe97ffea07cb2c3d",
              "status": "affected",
              "version": "c07dc84ed67c5a182273171639bacbbb87c12175",
              "versionType": "git"
            },
            {
              "lessThan": "b81572b073441dfd32213e41857676d0dbff4665",
              "status": "affected",
              "version": "8072e34e1387d03102b788677d491e2bcceef6f5",
              "versionType": "git"
            },
            {
              "lessThan": "b48f44f36e6607b2f818560f19deb86b4a9c717b",
              "status": "affected",
              "version": "8072e34e1387d03102b788677d491e2bcceef6f5",
              "versionType": "git"
            },
            {
              "lessThan": "6.18.33",
              "status": "affected",
              "version": "6.18.4",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "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"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "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",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "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",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/4584229395d0d65bd517780afe97ffea07cb2c3d"
        },
        {
          "url": "https://git.kernel.org/stable/c/b81572b073441dfd32213e41857676d0dbff4665"
        },
        {
          "url": "https://git.kernel.org/stable/c/b48f44f36e6607b2f818560f19deb86b4a9c717b"
        }
      ],
      "title": "NFSD: fix nfs4_file access extra count in nfsd4_add_rdaccess_to_wrdeleg",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "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"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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