CVE-2021-47316 (GCVE-0-2021-47316)

Vulnerability from cvelistv5 – Published: 2024-05-21 14:35 – Updated: 2026-08-05 08:47
VLAI
Title
nfsd: fix NULL dereference in nfs3svc_encode_getaclres
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix NULL dereference in nfs3svc_encode_getaclres In error cases the dentry may be NULL. Before 20798dfe249a, the encoder also checked dentry and d_really_is_positive(dentry), but that looks like overkill to me--zero status should be enough to guarantee a positive dentry. This isn't the first time we've seen an error-case NULL dereference hidden in the initialization of a local variable in an xdr encoder. But I went back through the other recent rewrites and didn't spot any similar bugs.
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-05-21 18:45 UTC
Assigner
Impacted products
Vendor Product Version
Linux Linux Affected: d505e66191072748620fc0af038cea4e4da0e3cd , < e79057d15d96ef19de4de6d7e479bae3d58a2a8d (git)
Affected: 20798dfe249a01ad1b12eec7dbc572db5003244a , < 650e6f383a6eb40f7c0a010982a74ab4b6893870 (git)
Affected: 20798dfe249a01ad1b12eec7dbc572db5003244a , < ab1016d39cc052064e32f25ad18ef8767a0ee3b8 (git)
Create a notification for this product.
Linux Linux Affected: 5.13
Unaffected: 0 , < 5.13 (semver)
Unaffected: 5.13.4 , ≤ 5.13.* (semver)
Unaffected: 5.14 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Siemens RUGGEDCOM RST2428P Unaffected: 0 , < * (custom)
Create a notification for this product.
Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family Unaffected: 0 , < * (custom)
Create a notification for this product.
Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family Unaffected: 0 , < * (custom)
Create a notification for this product.
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem Affected: 0 , < * (custom)
Create a notification for this product.
Show details on NVD website

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-47316",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-05-21T18:45:04.809482Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-06-04T17:13:36.645Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T05:32:08.599Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "affected": [
          {
            "defaultStatus": "unknown",
            "product": "RUGGEDCOM RST2428P",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "0",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "0",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SCALANCE XCM-/XRM-/XCH-/XRH-300 family",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "0",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "affected",
                "version": "0",
                "versionType": "custom"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-12T10:12:23.647Z",
          "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
          "shortName": "siemens-SADP"
        },
        "references": [
          {
            "url": "https://cert-portal.siemens.com/productcert/html/ssa-265688.html"
          },
          {
            "url": "https://cert-portal.siemens.com/productcert/html/ssa-355557.html"
          }
        ],
        "x_adpType": "supplier"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs3acl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e79057d15d96ef19de4de6d7e479bae3d58a2a8d",
              "status": "affected",
              "version": "d505e66191072748620fc0af038cea4e4da0e3cd",
              "versionType": "git"
            },
            {
              "lessThan": "650e6f383a6eb40f7c0a010982a74ab4b6893870",
              "status": "affected",
              "version": "20798dfe249a01ad1b12eec7dbc572db5003244a",
              "versionType": "git"
            },
            {
              "lessThan": "ab1016d39cc052064e32f25ad18ef8767a0ee3b8",
              "status": "affected",
              "version": "20798dfe249a01ad1b12eec7dbc572db5003244a",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfs3acl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.13"
            },
            {
              "lessThan": "5.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.13.*",
              "status": "unaffected",
              "version": "5.13.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.14",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.13.4",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.14",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix NULL dereference in nfs3svc_encode_getaclres\n\nIn error cases the dentry may be NULL.\n\nBefore 20798dfe249a, the encoder also checked dentry and\nd_really_is_positive(dentry), but that looks like overkill to me--zero\nstatus should be enough to guarantee a positive dentry.\n\nThis isn\u0027t the first time we\u0027ve seen an error-case NULL dereference\nhidden in the initialization of a local variable in an xdr encoder.  But\nI went back through the other recent rewrites and didn\u0027t spot any\nsimilar bugs."
        }
      ],
      "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 - The bug is in nfsd\u0027s NFSv3 ACL program (NFS_ACL_PROGRAM) GETACL result encoder, reached by sending RPC requests over the network to the in-kernel NFS server (TCP/UDP, typically port 2049).\nAC:L - An attacker reliably triggers the crash by sending a GETACL with a malformed or invalid filehandle so fh_verify fails and fh_dentry stays NULL; no race or attacker-uncontrollable condition is required.\nPR:N - The path is reachable with AUTH_NULL or forgeable AUTH_UNIX after only IP-based export matching, before any meaningful credential verification or valid filehandle access, matching other nfsd pre-auth/network DoS scores.\nUI:N - Exploitation requires only attacker-sent NFSACL GETACL RPCs; no victim user action is needed.\nS:U - Impact is confined to the NFS server host kernel; there is no VM escape, IOMMU bypass, or other cross-authority boundary crossing.\nC:N - This is a pure NULL pointer dereference of dentry-\u003ed_inode with no out-of-bounds read, UAF, or other information-disclosure primitive.\nI:N - The bug only crashes on NULL dereference in the encoder; it does not corrupt memory or provide a write/code-execution primitive.\nA:H - d_inode(NULL) causes a kernel oops/panic in nfsd, fully disrupting the NFS server and host availability, and can be repeated at will."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:47:14.619Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d"
        },
        {
          "url": "https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870"
        },
        {
          "url": "https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8"
        }
      ],
      "title": "nfsd: fix NULL dereference in nfs3svc_encode_getaclres",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47316",
    "datePublished": "2024-05-21T14:35:32.564Z",
    "dateReserved": "2024-05-21T14:28:16.973Z",
    "dateUpdated": "2026-08-05T08:47:14.619Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-47316",
      "date": "2026-08-15",
      "epss": "0.00622",
      "percentile": "0.46922"
    },
    "fkie_nvd": {
      "configurations": "[{\"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"versionStartIncluding\": \"5.13\", \"versionEndExcluding\": \"5.13.4\", \"matchCriteriaId\": \"F93FA3CC-0C79-410B-A7D7-245C2AA0723A\"}]}]}]",
      "descriptions": "[{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnfsd: fix NULL dereference in nfs3svc_encode_getaclres\\n\\nIn error cases the dentry may be NULL.\\n\\nBefore 20798dfe249a, the encoder also checked dentry and\\nd_really_is_positive(dentry), but that looks like overkill to me--zero\\nstatus should be enough to guarantee a positive dentry.\\n\\nThis isn\u0027t the first time we\u0027ve seen an error-case NULL dereference\\nhidden in the initialization of a local variable in an xdr encoder.  But\\nI went back through the other recent rewrites and didn\u0027t spot any\\nsimilar bugs.\"}, {\"lang\": \"es\", \"value\": \"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: nfsd: corrige la desreferencia NULL en nfs3svc_encode_getaclres. En casos de error, la dentry puede ser NULL. Antes de 20798dfe249a, el codificador tambi\\u00e9n verificaba dentry y d_really_is_positive(dentry), pero eso me parece excesivo: el estado cero deber\\u00eda ser suficiente para garantizar un dentry positivo. Esta no es la primera vez que vemos una desreferencia NULL de caso de error oculta en la inicializaci\\u00f3n de una variable local en un codificador xdr. Pero revis\\u00e9 las otras reescrituras recientes y no encontr\\u00e9 ning\\u00fan error similar.\"}]",
      "id": "CVE-2021-47316",
      "lastModified": "2024-12-24T16:28:58.957",
      "metrics": "{\"cvssMetricV31\": [{\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"cvssData\": {\"version\": \"3.1\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\", \"baseScore\": 5.5, \"baseSeverity\": \"MEDIUM\", \"attackVector\": \"LOCAL\", \"attackComplexity\": \"LOW\", \"privilegesRequired\": \"LOW\", \"userInteraction\": \"NONE\", \"scope\": \"UNCHANGED\", \"confidentialityImpact\": \"NONE\", \"integrityImpact\": \"NONE\", \"availabilityImpact\": \"HIGH\"}, \"exploitabilityScore\": 1.8, \"impactScore\": 3.6}]}",
      "published": "2024-05-21T15:15:18.940",
      "references": "[{\"url\": \"https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"tags\": [\"Patch\"]}, {\"url\": \"https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"tags\": [\"Patch\"]}, {\"url\": \"https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"tags\": [\"Patch\"]}, {\"url\": \"https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\", \"tags\": [\"Patch\"]}, {\"url\": \"https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\", \"tags\": [\"Patch\"]}, {\"url\": \"https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\", \"tags\": [\"Patch\"]}]",
      "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "vulnStatus": "Analyzed",
      "weaknesses": "[{\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"description\": [{\"lang\": \"en\", \"value\": \"CWE-476\"}]}]"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2021-47316\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-05-21T15:15:18.940\",\"lastModified\":\"2026-08-04T10:16:57.813\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnfsd: fix NULL dereference in nfs3svc_encode_getaclres\\n\\nIn error cases the dentry may be NULL.\\n\\nBefore 20798dfe249a, the encoder also checked dentry and\\nd_really_is_positive(dentry), but that looks like overkill to me--zero\\nstatus should be enough to guarantee a positive dentry.\\n\\nThis isn\u0027t the first time we\u0027ve seen an error-case NULL dereference\\nhidden in the initialization of a local variable in an xdr encoder.  But\\nI went back through the other recent rewrites and didn\u0027t spot any\\nsimilar bugs.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: nfsd: corrige la desreferencia NULL en nfs3svc_encode_getaclres. En casos de error, la dentry puede ser NULL. Antes de 20798dfe249a, el codificador tambi\u00e9n verificaba dentry y d_really_is_positive(dentry), pero eso me parece excesivo: el estado cero deber\u00eda ser suficiente para garantizar un dentry positivo. Esta no es la primera vez que vemos una desreferencia NULL de caso de error oculta en la inicializaci\u00f3n de una variable local en un codificador xdr. Pero revis\u00e9 las otras reescrituras recientes y no encontr\u00e9 ning\u00fan error similar.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/nfsd/nfs3acl.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"d505e66191072748620fc0af038cea4e4da0e3cd\",\"lessThan\":\"e79057d15d96ef19de4de6d7e479bae3d58a2a8d\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"20798dfe249a01ad1b12eec7dbc572db5003244a\",\"lessThan\":\"650e6f383a6eb40f7c0a010982a74ab4b6893870\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"20798dfe249a01ad1b12eec7dbc572db5003244a\",\"lessThan\":\"ab1016d39cc052064e32f25ad18ef8767a0ee3b8\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/nfsd/nfs3acl.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.13\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.13\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.13.4\",\"lessThanOrEqual\":\"5.13.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.14\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]},{\"source\":\"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e\",\"affectedData\":[{\"vendor\":\"Siemens\",\"product\":\"RUGGEDCOM RST2428P\",\"defaultStatus\":\"unknown\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"*\",\"versionType\":\"custom\",\"status\":\"unaffected\"}]},{\"vendor\":\"Siemens\",\"product\":\"SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family\",\"defaultStatus\":\"unknown\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"*\",\"versionType\":\"custom\",\"status\":\"unaffected\"}]},{\"vendor\":\"Siemens\",\"product\":\"SCALANCE XCM-/XRM-/XCH-/XRH-300 family\",\"defaultStatus\":\"unknown\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"*\",\"versionType\":\"custom\",\"status\":\"unaffected\"}]},{\"vendor\":\"Siemens\",\"product\":\"SIMATIC S7-1500 TM MFP - GNU/Linux subsystem\",\"defaultStatus\":\"unknown\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"*\",\"versionType\":\"custom\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":5.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":3.6}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2024-05-21T18:45:04.809482Z\",\"id\":\"CVE-2021-47316\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-476\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.13\",\"versionEndExcluding\":\"5.13.4\",\"matchCriteriaId\":\"F93FA3CC-0C79-410B-A7D7-245C2AA0723A\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://cert-portal.siemens.com/productcert/html/ssa-265688.html\",\"source\":\"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e\"},{\"url\":\"https://cert-portal.siemens.com/productcert/html/ssa-355557.html\",\"source\":\"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-04T19:59:40+00:00",
      "cve": "CVE-2021-47316",
      "id": "CVE-2021-47316",
      "initial_release_date": "2021-01-01T00:00:00+00:00",
      "product_status:known_affected": "196",
      "product_status:known_not_affected": "2",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: nfsd: fix NULL dereference in nfs3svc_encode_getaclres",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-47316.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-07-23T02:38:53Z",
      "cve": "CVE-2021-47316",
      "id": "CVE-2021-47316",
      "initial_release_date": "2024-05-23T03:04:46Z",
      "product_status:known_not_affected": "330",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-47316",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-47316.json",
      "version": "19"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8\", \"tags\": [\"x_transferred\"]}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2024-08-04T05:32:08.599Z\"}}, {\"affected\": [{\"vendor\": \"Siemens\", \"product\": \"RUGGEDCOM RST2428P\", \"versions\": [{\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"*\", \"versionType\": \"custom\"}], \"defaultStatus\": \"unknown\"}, {\"vendor\": \"Siemens\", \"product\": \"SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family\", \"versions\": [{\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"*\", \"versionType\": \"custom\"}], \"defaultStatus\": \"unknown\"}, {\"vendor\": \"Siemens\", \"product\": \"SCALANCE XCM-/XRM-/XCH-/XRH-300 family\", \"versions\": [{\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"*\", \"versionType\": \"custom\"}], \"defaultStatus\": \"unknown\"}, {\"vendor\": \"Siemens\", \"product\": \"SIMATIC S7-1500 TM MFP - GNU/Linux subsystem\", \"versions\": [{\"status\": \"affected\", \"version\": \"0\", \"lessThan\": \"*\", \"versionType\": \"custom\"}], \"defaultStatus\": \"unknown\"}], \"x_adpType\": \"supplier\", \"references\": [{\"url\": \"https://cert-portal.siemens.com/productcert/html/ssa-265688.html\"}, {\"url\": \"https://cert-portal.siemens.com/productcert/html/ssa-355557.html\"}], \"providerMetadata\": {\"orgId\": \"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e\", \"shortName\": \"siemens-SADP\", \"dateUpdated\": \"2026-05-12T10:12:23.647Z\"}}, {\"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2021-47316\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2024-05-21T18:45:04.809482Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2024-05-23T19:01:25.477Z\"}, \"title\": \"CISA ADP Vulnrichment\"}], \"cna\": {\"title\": \"nfsd: fix NULL dereference in nfs3svc_encode_getaclres\", \"metrics\": [{\"cvssV3_1\": {\"version\": \"3.1\", \"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\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"AV:N - The bug is in nfsd\u0027s NFSv3 ACL program (NFS_ACL_PROGRAM) GETACL result encoder, reached by sending RPC requests over the network to the in-kernel NFS server (TCP/UDP, typically port 2049).\\nAC:L - An attacker reliably triggers the crash by sending a GETACL with a malformed or invalid filehandle so fh_verify fails and fh_dentry stays NULL; no race or attacker-uncontrollable condition is required.\\nPR:N - The path is reachable with AUTH_NULL or forgeable AUTH_UNIX after only IP-based export matching, before any meaningful credential verification or valid filehandle access, matching other nfsd pre-auth/network DoS scores.\\nUI:N - Exploitation requires only attacker-sent NFSACL GETACL RPCs; no victim user action is needed.\\nS:U - Impact is confined to the NFS server host kernel; there is no VM escape, IOMMU bypass, or other cross-authority boundary crossing.\\nC:N - This is a pure NULL pointer dereference of dentry-\u003ed_inode with no out-of-bounds read, UAF, or other information-disclosure primitive.\\nI:N - The bug only crashes on NULL dereference in the encoder; it does not corrupt memory or provide a write/code-execution primitive.\\nA:H - d_inode(NULL) causes a kernel oops/panic in nfsd, fully disrupting the NFS server and host availability, and can be repeated at will.\"}]}], \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"d505e66191072748620fc0af038cea4e4da0e3cd\", \"lessThan\": \"e79057d15d96ef19de4de6d7e479bae3d58a2a8d\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"20798dfe249a01ad1b12eec7dbc572db5003244a\", \"lessThan\": \"650e6f383a6eb40f7c0a010982a74ab4b6893870\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"20798dfe249a01ad1b12eec7dbc572db5003244a\", \"lessThan\": \"ab1016d39cc052064e32f25ad18ef8767a0ee3b8\", \"versionType\": \"git\"}], \"programFiles\": [\"fs/nfsd/nfs3acl.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"5.13\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"5.13\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.13.4\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.13.*\"}, {\"status\": \"unaffected\", \"version\": \"5.14\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"fs/nfsd/nfs3acl.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d\"}, {\"url\": \"https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870\"}, {\"url\": \"https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnfsd: fix NULL dereference in nfs3svc_encode_getaclres\\n\\nIn error cases the dentry may be NULL.\\n\\nBefore 20798dfe249a, the encoder also checked dentry and\\nd_really_is_positive(dentry), but that looks like overkill to me--zero\\nstatus should be enough to guarantee a positive dentry.\\n\\nThis isn\u0027t the first time we\u0027ve seen an error-case NULL dereference\\nhidden in the initialization of a local variable in an xdr encoder.  But\\nI went back through the other recent rewrites and didn\u0027t spot any\\nsimilar bugs.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.13.4\", \"versionStartIncluding\": \"5.13\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.14\", \"versionStartIncluding\": \"5.13\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T08:47:14.619Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2021-47316\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-05T08:47:14.619Z\", \"dateReserved\": \"2024-05-21T14:28:16.973Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-05-21T14:35:32.564Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.


Loading…

Loading…

Loading…

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.

Loading…

Detection rules are retrieved from Rulezet.

Loading…

Loading…

Loading…