GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2021-20239 (GCVE-0-2021-20239)

Vulnerability from cvelistv5 – Published: 2021-05-28 10:42 – Updated: 2024-08-03 17:37
VLAI
Summary
A flaw was found in the Linux kernel in versions before 5.4.92 in the BPF protocol. This flaw allows an attacker with a local account to leak information about kernel internal addresses. The highest threat from this vulnerability is to confidentiality.
Severity
3.3 (Low)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
n/a kernel Affected: kernel 5.4.92
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T17:37:22.636Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1923636"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "kernel",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "kernel 5.4.92"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "A flaw was found in the Linux kernel in versions before 5.4.92 in the BPF protocol. This flaw allows an attacker with a local account to leak information about kernel internal addresses. The highest threat from this vulnerability is to confidentiality."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-822",
              "description": "CWE-822-\u003eCWE-200",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2021-05-28T10:42:29.000Z",
        "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "shortName": "redhat"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1923636"
        }
      ],
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "secalert@redhat.com",
          "ID": "CVE-2021-20239",
          "STATE": "PUBLIC"
        },
        "affects": {
          "vendor": {
            "vendor_data": [
              {
                "product": {
                  "product_data": [
                    {
                      "product_name": "kernel",
                      "version": {
                        "version_data": [
                          {
                            "version_value": "kernel 5.4.92"
                          }
                        ]
                      }
                    }
                  ]
                },
                "vendor_name": "n/a"
              }
            ]
          }
        },
        "data_format": "MITRE",
        "data_type": "CVE",
        "data_version": "4.0",
        "description": {
          "description_data": [
            {
              "lang": "eng",
              "value": "A flaw was found in the Linux kernel in versions before 5.4.92 in the BPF protocol. This flaw allows an attacker with a local account to leak information about kernel internal addresses. The highest threat from this vulnerability is to confidentiality."
            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "eng",
                  "value": "CWE-822-\u003eCWE-200"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://bugzilla.redhat.com/show_bug.cgi?id=1923636",
              "refsource": "MISC",
              "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1923636"
            }
          ]
        }
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
    "assignerShortName": "redhat",
    "cveId": "CVE-2021-20239",
    "datePublished": "2021-05-28T10:42:29.000Z",
    "dateReserved": "2020-12-17T00:00:00.000Z",
    "dateUpdated": "2024-08-03T17:37:22.636Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-20239",
      "date": "2026-09-15",
      "epss": "0.00255",
      "percentile": "0.17249"
    },
    "fkie_nvd": {
      "configurations": "[{\"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"versionEndExcluding\": \"5.4.92\", \"matchCriteriaId\": \"6B130008-5C96-49EE-9BC8-E954F395A514\"}]}]}, {\"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:redhat:enterprise_linux:5.0:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"1D8B549B-E57B-4DFE-8A13-CAB06B5356B3\"}, {\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"2F6AB192-9D7D-4A9A-8995-E53A9DE9EAFC\"}, {\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"F4CFF558-3C47-480D-A2F0-BABF26042943\"}]}]}, {\"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"E460AA51-FCDA-46B9-AE97-E6676AA5E194\"}]}]}]",
      "descriptions": "[{\"lang\": \"en\", \"value\": \"A flaw was found in the Linux kernel in versions before 5.4.92 in the BPF protocol. This flaw allows an attacker with a local account to leak information about kernel internal addresses. The highest threat from this vulnerability is to confidentiality.\"}, {\"lang\": \"es\", \"value\": \"Se encontr\\u00f3 un fallo en el kernel de Linux en versiones anteriores a 5.4.92 en el protocolo BPF.\u0026#xa0;Este fallo permite a un atacante con una cuenta local filtrar informaci\\u00f3n sobre las direcciones internas del kernel.\u0026#xa0;La mayor amenaza de esta vulnerabilidad es la confidencialidad\"}]",
      "id": "CVE-2021-20239",
      "lastModified": "2024-11-21T05:46:11.713",
      "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:L/I:N/A:N\", \"baseScore\": 3.3, \"baseSeverity\": \"LOW\", \"attackVector\": \"LOCAL\", \"attackComplexity\": \"LOW\", \"privilegesRequired\": \"LOW\", \"userInteraction\": \"NONE\", \"scope\": \"UNCHANGED\", \"confidentialityImpact\": \"LOW\", \"integrityImpact\": \"NONE\", \"availabilityImpact\": \"NONE\"}, \"exploitabilityScore\": 1.8, \"impactScore\": 1.4}], \"cvssMetricV2\": [{\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"cvssData\": {\"version\": \"2.0\", \"vectorString\": \"AV:L/AC:L/Au:N/C:P/I:N/A:N\", \"baseScore\": 2.1, \"accessVector\": \"LOCAL\", \"accessComplexity\": \"LOW\", \"authentication\": \"NONE\", \"confidentialityImpact\": \"PARTIAL\", \"integrityImpact\": \"NONE\", \"availabilityImpact\": \"NONE\"}, \"baseSeverity\": \"LOW\", \"exploitabilityScore\": 3.9, \"impactScore\": 2.9, \"acInsufInfo\": false, \"obtainAllPrivilege\": false, \"obtainUserPrivilege\": false, \"obtainOtherPrivilege\": false, \"userInteractionRequired\": false}]}",
      "published": "2021-05-28T11:15:08.003",
      "references": "[{\"url\": \"https://bugzilla.redhat.com/show_bug.cgi?id=1923636\", \"source\": \"secalert@redhat.com\", \"tags\": [\"Issue Tracking\", \"Third Party Advisory\"]}, {\"url\": \"https://bugzilla.redhat.com/show_bug.cgi?id=1923636\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\", \"tags\": [\"Issue Tracking\", \"Third Party Advisory\"]}]",
      "sourceIdentifier": "secalert@redhat.com",
      "vulnStatus": "Modified",
      "weaknesses": "[{\"source\": \"secalert@redhat.com\", \"type\": \"Secondary\", \"description\": [{\"lang\": \"en\", \"value\": \"CWE-822\"}]}, {\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"description\": [{\"lang\": \"en\", \"value\": \"CWE-119\"}]}]"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2021-20239\",\"sourceIdentifier\":\"secalert@redhat.com\",\"published\":\"2021-05-28T11:15:08.003\",\"lastModified\":\"2024-11-21T05:46:11.713\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"A flaw was found in the Linux kernel in versions before 5.4.92 in the BPF protocol. This flaw allows an attacker with a local account to leak information about kernel internal addresses. The highest threat from this vulnerability is to confidentiality.\"},{\"lang\":\"es\",\"value\":\"Se encontr\u00f3 un fallo en el kernel de Linux en versiones anteriores a 5.4.92 en el protocolo BPF.\u0026#xa0;Este fallo permite a un atacante con una cuenta local filtrar informaci\u00f3n sobre las direcciones internas del kernel.\u0026#xa0;La mayor amenaza de esta vulnerabilidad es la confidencialidad\"}],\"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:L/I:N/A:N\",\"baseScore\":3.3,\"baseSeverity\":\"LOW\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":1.8,\"impactScore\":1.4}],\"cvssMetricV2\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"2.0\",\"vectorString\":\"AV:L/AC:L/Au:N/C:P/I:N/A:N\",\"baseScore\":2.1,\"accessVector\":\"LOCAL\",\"accessComplexity\":\"LOW\",\"authentication\":\"NONE\",\"confidentialityImpact\":\"PARTIAL\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"baseSeverity\":\"LOW\",\"exploitabilityScore\":3.9,\"impactScore\":2.9,\"acInsufInfo\":false,\"obtainAllPrivilege\":false,\"obtainUserPrivilege\":false,\"obtainOtherPrivilege\":false,\"userInteractionRequired\":false}]},\"weaknesses\":[{\"source\":\"secalert@redhat.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-822\"}]},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-119\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"5.4.92\",\"matchCriteriaId\":\"6B130008-5C96-49EE-9BC8-E954F395A514\"}]}]},{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:redhat:enterprise_linux:5.0:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"1D8B549B-E57B-4DFE-8A13-CAB06B5356B3\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"2F6AB192-9D7D-4A9A-8995-E53A9DE9EAFC\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"F4CFF558-3C47-480D-A2F0-BABF26042943\"}]}]},{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"E460AA51-FCDA-46B9-AE97-E6676AA5E194\"}]}]}],\"references\":[{\"url\":\"https://bugzilla.redhat.com/show_bug.cgi?id=1923636\",\"source\":\"secalert@redhat.com\",\"tags\":[\"Issue Tracking\",\"Third Party Advisory\"]},{\"url\":\"https://bugzilla.redhat.com/show_bug.cgi?id=1923636\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Issue Tracking\",\"Third Party Advisory\"]}]}}",
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-06-28T07:42:29+00:00",
      "cve": "CVE-2021-20239",
      "id": "CVE-2021-20239",
      "initial_release_date": "2021-02-01T00:00:00+00:00",
      "product_status:fixed": "150",
      "product_status:known_affected": "15",
      "product_status:known_not_affected": "135",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: setsockopt System Call Untrusted Pointer Dereference Information Disclosure",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-20239.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-31T02:08:59Z",
      "cve": "CVE-2021-20239",
      "id": "CVE-2021-20239",
      "initial_release_date": "2023-02-15T03:47:24Z",
      "product_status:known_not_affected": "422",
      "product_status:recommended": "20",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-20239",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-20239.json",
      "version": "15"
    }
  }
}



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.


Detection rules are retrieved from Rulezet.


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.