CVE-2021-47312 (GCVE-0-2021-47312)

Vulnerability from cvelistv5 – Published: 2024-05-21 14:35 – Updated: 2026-05-11 13:52
VLAI
Title
netfilter: nf_tables: Fix dereference of null pointer flow
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: Fix dereference of null pointer flow In the case where chain->flags & NFT_CHAIN_HW_OFFLOAD is false then nft_flow_rule_create is not called and flow is NULL. The subsequent error handling execution via label err_destroy_flow_rule will lead to a null pointer dereference on flow when calling nft_flow_rule_destroy. Since the error path to err_destroy_flow_rule has to cater for null and non-null flows, only call nft_flow_rule_destroy if flow is non-null to fix this issue. Addresses-Coverity: ("Explicity null dereference")
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-05-29 18:11 UTC
CWE
  • CWE-476 - NULL Pointer Dereference
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 09b1f676e2e0bbff67c568672c565c6f31470157 , < 70a5a1950cca02c5cd161bb3846b4d983eed97d3 (git)
Affected: 3c5e44622011b9ea21bd425875dcccfc9a158f5f , < 4ca041f919f13783b0b03894783deee00dbca19a (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.13.2 , < 5.13.5 (semver)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 5.5,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2021-47312",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-05-29T18:11:18.013824Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-476",
                "description": "CWE-476 NULL Pointer Dereference",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-11-05T14:44:02.835Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T05:32:08.515Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/70a5a1950cca02c5cd161bb3846b4d983eed97d3"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/4ca041f919f13783b0b03894783deee00dbca19a"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_tables_api.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "70a5a1950cca02c5cd161bb3846b4d983eed97d3",
              "status": "affected",
              "version": "09b1f676e2e0bbff67c568672c565c6f31470157",
              "versionType": "git"
            },
            {
              "lessThan": "4ca041f919f13783b0b03894783deee00dbca19a",
              "status": "affected",
              "version": "3c5e44622011b9ea21bd425875dcccfc9a158f5f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_tables_api.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5.13.5",
              "status": "affected",
              "version": "5.13.2",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.13.5",
                  "versionStartIncluding": "5.13.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: Fix dereference of null pointer flow\n\nIn the case where chain-\u003eflags \u0026 NFT_CHAIN_HW_OFFLOAD is false then\nnft_flow_rule_create is not called and flow is NULL. The subsequent\nerror handling execution via label err_destroy_flow_rule will lead\nto a null pointer dereference on flow when calling nft_flow_rule_destroy.\nSince the error path to err_destroy_flow_rule has to cater for null\nand non-null flows, only call nft_flow_rule_destroy if flow is non-null\nto fix this issue.\n\nAddresses-Coverity: (\"Explicity null dereference\")"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T13:52:03.687Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/70a5a1950cca02c5cd161bb3846b4d983eed97d3"
        },
        {
          "url": "https://git.kernel.org/stable/c/4ca041f919f13783b0b03894783deee00dbca19a"
        }
      ],
      "title": "netfilter: nf_tables: Fix dereference of null pointer flow",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47312",
    "datePublished": "2024-05-21T14:35:29.963Z",
    "dateReserved": "2024-05-21T14:28:16.973Z",
    "dateUpdated": "2026-05-11T13:52:03.687Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-47312",
      "date": "2026-10-06",
      "epss": "0.0022",
      "percentile": "0.11467"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "net/netfilter/nf_tables_api.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "70a5a1950cca02c5cd161bb3846b4d983eed97d3",
                    "status": "affected",
                    "version": "09b1f676e2e0bbff67c568672c565c6f31470157",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "4ca041f919f13783b0b03894783deee00dbca19a",
                    "status": "affected",
                    "version": "3c5e44622011b9ea21bd425875dcccfc9a158f5f",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "net/netfilter/nf_tables_api.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "5.13.5",
                    "status": "affected",
                    "version": "5.13.2",
                    "versionType": "semver"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "8BF6AAC6-D649-4E4F-98AE-B880144C2196",
                    "versionEndExcluding": "5.13.5",
                    "versionStartIncluding": "5.13.2",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: Fix dereference of null pointer flow\n\nIn the case where chain-\u003eflags \u0026 NFT_CHAIN_HW_OFFLOAD is false then\nnft_flow_rule_create is not called and flow is NULL. The subsequent\nerror handling execution via label err_destroy_flow_rule will lead\nto a null pointer dereference on flow when calling nft_flow_rule_destroy.\nSince the error path to err_destroy_flow_rule has to cater for null\nand non-null flows, only call nft_flow_rule_destroy if flow is non-null\nto fix this issue.\n\nAddresses-Coverity: (\"Explicity null dereference\")"
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: netfilter: nf_tables: corrige la desreferencia del flujo de puntero null. En el caso de que chain-\u0026gt;flags \u0026amp; NFT_CHAIN_HW_OFFLOAD sea falso, no se llama a nft_flow_rule_create y el flujo es NULL. La ejecuci\u00f3n posterior del manejo de errores a trav\u00e9s de la etiqueta err_destroy_flow_rule dar\u00e1 lugar a una desreferencia del puntero null en el flujo al llamar a nft_flow_rule_destroy. Dado que la ruta de error a err_destroy_flow_rule tiene que atender flujos nulos y no nulos, solo llame a nft_flow_rule_destroy si el flujo no es nulo para solucionar este problema. Direcciones-Cobertura: (\"Desreferencia nula expl\u00edcita\")"
          }
        ],
        "id": "CVE-2021-47312",
        "lastModified": "2026-06-17T04:17:10.103",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 5.5,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 3.6,
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2021-47312",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-05-29T18:11:18.013824Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2024-05-21T15:15:18.660",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/4ca041f919f13783b0b03894783deee00dbca19a"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/70a5a1950cca02c5cd161bb3846b4d983eed97d3"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/4ca041f919f13783b0b03894783deee00dbca19a"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/70a5a1950cca02c5cd161bb3846b4d983eed97d3"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-476"
              }
            ],
            "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2025-11-21T14:36:33+00:00",
      "cve": "CVE-2021-47312",
      "id": "CVE-2021-47312",
      "initial_release_date": "2021-01-01T00:00:00+00:00",
      "product_status:known_affected": "42",
      "product_status:known_not_affected": "156",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: netfilter: nf_tables: Fix dereference of null pointer flow",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-47312.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "providerMetadata": {
              "dateUpdated": "2024-08-04T05:32:08.515Z",
              "orgId": "af854a3a-2127-422b-91ae-364da2661108",
              "shortName": "CVE"
            },
            "references": [
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://git.kernel.org/stable/c/70a5a1950cca02c5cd161bb3846b4d983eed97d3"
              },
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://git.kernel.org/stable/c/4ca041f919f13783b0b03894783deee00dbca19a"
              }
            ],
            "title": "CVE Program Container"
          },
          {
            "metrics": [
              {
                "cvssV3_1": {
                  "attackComplexity": "LOW",
                  "attackVector": "LOCAL",
                  "availabilityImpact": "HIGH",
                  "baseScore": 5.5,
                  "baseSeverity": "MEDIUM",
                  "confidentialityImpact": "NONE",
                  "integrityImpact": "NONE",
                  "privilegesRequired": "LOW",
                  "scope": "UNCHANGED",
                  "userInteraction": "NONE",
                  "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                  "version": "3.1"
                }
              },
              {
                "other": {
                  "content": {
                    "id": "CVE-2021-47312",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2024-05-29T18:11:18.013824Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "cweId": "CWE-476",
                    "description": "CWE-476 NULL Pointer Dereference",
                    "lang": "en",
                    "type": "CWE"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2024-05-29T18:11:21.757Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "net/netfilter/nf_tables_api.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "70a5a1950cca",
                  "status": "affected",
                  "version": "09b1f676e2e0",
                  "versionType": "git"
                },
                {
                  "lessThan": "4ca041f919f1",
                  "status": "affected",
                  "version": "3c5e44622011",
                  "versionType": "git"
                }
              ]
            },
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "net/netfilter/nf_tables_api.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "5.13.5",
                  "status": "affected",
                  "version": "5.13.2",
                  "versionType": "semver"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: Fix dereference of null pointer flow\n\nIn the case where chain-\u003eflags \u0026 NFT_CHAIN_HW_OFFLOAD is false then\nnft_flow_rule_create is not called and flow is NULL. The subsequent\nerror handling execution via label err_destroy_flow_rule will lead\nto a null pointer dereference on flow when calling nft_flow_rule_destroy.\nSince the error path to err_destroy_flow_rule has to cater for null\nand non-null flows, only call nft_flow_rule_destroy if flow is non-null\nto fix this issue.\n\nAddresses-Coverity: (\"Explicity null dereference\")"
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2024-11-04T11:38:47.423Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
          "references": [
            {
              "url": "https://git.kernel.org/stable/c/70a5a1950cca02c5cd161bb3846b4d983eed97d3"
            },
            {
              "url": "https://git.kernel.org/stable/c/4ca041f919f13783b0b03894783deee00dbca19a"
            }
          ],
          "title": "netfilter: nf_tables: Fix dereference of null pointer flow",
          "x_generator": {
            "engine": "bippy-c8e10e5f6187"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2021-47312",
        "datePublished": "2024-05-21T14:35:29.963Z",
        "dateReserved": "2024-05-21T14:28:16.973Z",
        "dateUpdated": "2024-11-05T14:44:02.835Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.