{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfsfh.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "b6bc86ce3944b10b9fc181fc00c1a520a20ed965",
              "status": "affected",
              "version": "ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444",
              "versionType": "git"
            },
            {
              "lessThan": "8a7348a9ed70bda1c1f51d3f1815bcbdf9f3b38c",
              "status": "affected",
              "version": "ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfsfh.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.12"
            },
            {
              "lessThan": "6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.59",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.17.*",
              "status": "unaffected",
              "version": "6.17.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18-rc6",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.59",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17.9",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18-rc6",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix refcount leak in nfsd_set_fh_dentry()\n\nnfsd exports a \"pseudo root filesystem\" which is used by NFSv4 to find\nthe various exported filesystems using LOOKUP requests from a known root\nfilehandle.  NFSv3 uses the MOUNT protocol to find those exported\nfilesystems and so is not given access to the pseudo root filesystem.\n\nIf a v3 (or v2) client uses a filehandle from that filesystem,\nnfsd_set_fh_dentry() will report an error, but still stores the export\nin \"struct svc_fh\" even though it also drops the reference (exp_put()).\nThis means that when fh_put() is called an extra reference will be dropped\nwhich can lead to use-after-free and possible denial of service.\n\nNormal NFS usage will not provide a pseudo-root filehandle to a v3\nclient.  This bug can only be triggered by the client synthesising an\nincorrect filehandle.\n\nTo fix this we move the assignments to the svc_fh later, after all\npossible error cases have been detected."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-11-24T13:04:20.888Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b6bc86ce3944b10b9fc181fc00c1a520a20ed965"
        },
        {
          "url": "https://git.kernel.org/stable/c/c83d7365cec5eb5ebeeee2a72e29b4ca58a7e4c2"
        },
        {
          "url": "https://git.kernel.org/stable/c/8a7348a9ed70bda1c1f51d3f1815bcbdf9f3b38c"
        }
      ],
      "title": "nfsd: fix refcount leak in nfsd_set_fh_dentry()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-40212",
    "datePublished": "2025-11-24T13:04:20.888Z",
    "dateReserved": "2025-04-16T07:20:57.179Z",
    "dateUpdated": "2025-11-24T13:04:20.888Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-40212\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-11-24T13:16:02.813\",\"lastModified\":\"2025-11-24T13:16:02.813\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnfsd: fix refcount leak in nfsd_set_fh_dentry()\\n\\nnfsd exports a \\\"pseudo root filesystem\\\" which is used by NFSv4 to find\\nthe various exported filesystems using LOOKUP requests from a known root\\nfilehandle.  NFSv3 uses the MOUNT protocol to find those exported\\nfilesystems and so is not given access to the pseudo root filesystem.\\n\\nIf a v3 (or v2) client uses a filehandle from that filesystem,\\nnfsd_set_fh_dentry() will report an error, but still stores the export\\nin \\\"struct svc_fh\\\" even though it also drops the reference (exp_put()).\\nThis means that when fh_put() is called an extra reference will be dropped\\nwhich can lead to use-after-free and possible denial of service.\\n\\nNormal NFS usage will not provide a pseudo-root filehandle to a v3\\nclient.  This bug can only be triggered by the client synthesising an\\nincorrect filehandle.\\n\\nTo fix this we move the assignments to the svc_fh later, after all\\npossible error cases have been detected.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/8a7348a9ed70bda1c1f51d3f1815bcbdf9f3b38c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b6bc86ce3944b10b9fc181fc00c1a520a20ed965\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c83d7365cec5eb5ebeeee2a72e29b4ca58a7e4c2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}