Vulnerability-Lookup

GSD-2020-8562

Vulnerability from gsd - Updated: 2023-12-13 01:21

Details

As mitigations to a report from 2019 and CVE-2020-8555, Kubernetes attempts to prevent proxied connections from accessing link-local or localhost networks when making user-driven connections to Services, Pods, Nodes, or StorageClass service providers. As part of this mitigation Kubernetes does a DNS name resolution check and validates that response IPs are not in the link-local (169.254.0.0/16) or localhost (127.0.0.0/8) range. Kubernetes then performs a second DNS resolution without validation for the actual connection. If a non-standard DNS server returns different non-cached responses, a user may be able to bypass the proxy IP restriction and access private networks on the control plane.

Aliases

CVE-2020-8562

Aliases

CVE-2020-8562

JSON

To clipboard

{
  "GSD": {
    "alias": "CVE-2020-8562",
    "description": "As mitigations to a report from 2019 and CVE-2020-8555, Kubernetes attempts to prevent proxied connections from accessing link-local or localhost networks when making user-driven connections to Services, Pods, Nodes, or StorageClass service providers. As part of this mitigation Kubernetes does a DNS name resolution check and validates that response IPs are not in the link-local (169.254.0.0/16) or localhost (127.0.0.0/8) range. Kubernetes then performs a second DNS resolution without validation for the actual connection. If a non-standard DNS server returns different non-cached responses, a user may be able to bypass the proxy IP restriction and access private networks on the control plane.",
    "id": "GSD-2020-8562",
    "references": [
      "https://www.suse.com/security/cve/CVE-2020-8562.html",
      "https://security.archlinux.org/CVE-2020-8562"
    ]
  },
  "gsd": {
    "metadata": {
      "exploitCode": "unknown",
      "remediation": "unknown",
      "reportConfidence": "confirmed",
      "type": "vulnerability"
    },
    "osvSchema": {
      "aliases": [
        "CVE-2020-8562"
      ],
      "details": "As mitigations to a report from 2019 and CVE-2020-8555, Kubernetes attempts to prevent proxied connections from accessing link-local or localhost networks when making user-driven connections to Services, Pods, Nodes, or StorageClass service providers. As part of this mitigation Kubernetes does a DNS name resolution check and validates that response IPs are not in the link-local (169.254.0.0/16) or localhost (127.0.0.0/8) range. Kubernetes then performs a second DNS resolution without validation for the actual connection. If a non-standard DNS server returns different non-cached responses, a user may be able to bypass the proxy IP restriction and access private networks on the control plane.",
      "id": "GSD-2020-8562",
      "modified": "2023-12-13T01:21:53.364157Z",
      "schema_version": "1.4.0"
    }
  },
  "namespaces": {
    "cve.org": {
      "CVE_data_meta": {
        "ASSIGNER": "security@kubernetes.io",
        "DATE_PUBLIC": "2021-05-04T16:51:00.000Z",
        "ID": "CVE-2020-8562",
        "STATE": "PUBLIC",
        "TITLE": "Bypass of Kubernetes API Server proxy TOCTOU"
      },
      "affects": {
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                          "version_value": "v1.21.0"
                        },
                        {
                          "version_affected": "?\u003e",
                          "version_value": "v1.21.0"
                        }
                      ]
                    }
                  }
                ]
              },
              "vendor_name": "Kubernetes"
            }
          ]
        }
      },
      "credit": [
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          "value": "Javier Provecho"
        }
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          }
        ]
      },
      "generator": {
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      },
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          "baseSeverity": "LOW",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "HIGH",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N",
          "version": "3.1"
        }
      },
      "problemtype": {
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          {
            "description": [
              {
                "lang": "eng",
                "value": "CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition"
              }
            ]
          }
        ]
      },
      "references": {
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          {
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            "refsource": "MISC",
            "url": "https://groups.google.com/g/kubernetes-security-announce/c/-MFX60_wdOY"
          },
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            "name": "https://security.netapp.com/advisory/ntap-20220225-0002/",
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          }
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        }
      ]
    },
    "gitlab.com": {
      "advisories": [
        {
          "affected_range": "\u003e=1.21.0 \u003c1.21.1||\u003e=1.20.0 \u003c1.20.7||\u003e=1.19.0 \u003c1.19.11||\u003c1.18.19",
          "affected_versions": "All versions starting from 1.21.0 before 1.21.1, all versions starting from 1.20.0 before 1.20.7, all versions starting from 1.19.0 before 1.19.11, all versions before 1.18.19",
          "cvss_v2": "AV:N/AC:M/Au:S/C:P/I:N/A:N",
          "cvss_v3": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N",
          "cwe_ids": [
            "CWE-1035",
            "CWE-367",
            "CWE-937"
          ],
          "date": "2022-02-11",
          "description": "As mitigations to a report from 2019 and CVE-2020-8555, Kubernetes attempts to prevent proxied connections from accessing link-local or localhost networks when making user-driven connections to Services, Pods, Nodes, or StorageClass service providers. As part of this mitigation Kubernetes does a DNS name resolution check and validates that response IPs are not in the link-local (169.254.0.0/16) or localhost (127.0.0.0/8) range. Kubernetes then performs a second DNS resolution without validation for the actual connection. If a non-standard DNS server returns different non-cached responses, a user may be able to bypass the proxy IP restriction and access private networks on the control plane.",
          "fixed_versions": [
            "1.21.1",
            "1.21.1",
            "1.19.11",
            "1.18.19",
            "1.18.19"
          ],
          "identifier": "CVE-2020-8562",
          "identifiers": [
            "GHSA-qh36-44jv-c8xj",
            "CVE-2020-8562"
          ],
          "not_impacted": "All versions before 1.21.0, all versions starting from 1.21.1, all versions before 1.20.0, all versions starting from 1.20.7, all versions before 1.19.0, all versions starting from 1.18.19 before 1.19.11",
          "package_slug": "go/k8s.io/kubernetes",
          "pubdate": "2022-02-02",
          "solution": "Upgrade to versions 1.21.1, 1.21.1, 1.19.11, 1.18.19, 1.18.19 or above.",
          "title": "Time-of-check Time-of-use (TOCTOU) Race Condition",
          "urls": [
            "https://nvd.nist.gov/vuln/detail/CVE-2020-8562",
            "https://github.com/kubernetes/kubernetes/issues/101493",
            "https://groups.google.com/g/kubernetes-security-announce/c/-MFX60_wdOY",
            "https://github.com/advisories/GHSA-qh36-44jv-c8xj"
          ],
          "uuid": "1b421428-da20-49dc-8920-6d0473cc8e4b"
        }
      ]
    },
    "nvd.nist.gov": {
      "configurations": {
        "CVE_data_version": "4.0",
        "nodes": [
          {
            "children": [],
            "cpe_match": [
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                "cpe_name": [],
                "versionEndIncluding": "1.18.18",
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              },
              {
                "cpe23Uri": "cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*",
                "cpe_name": [],
                "versionEndIncluding": "1.19.10",
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              },
              {
                "cpe23Uri": "cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*",
                "cpe_name": [],
                "versionEndIncluding": "1.20.6",
                "versionStartIncluding": "1.20.0",
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              },
              {
                "cpe23Uri": "cpe:2.3:a:kubernetes:kubernetes:1.21.0:*:*:*:*:*:*:*",
                "cpe_name": [],
                "vulnerable": true
              }
            ],
            "operator": "OR"
          }
        ]
      },
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            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "en",
                  "value": "CWE-367"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://groups.google.com/g/kubernetes-security-announce/c/-MFX60_wdOY",
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              "tags": [
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                "Third Party Advisory"
              ],
              "url": "https://groups.google.com/g/kubernetes-security-announce/c/-MFX60_wdOY"
            },
            {
              "name": "https://github.com/kubernetes/kubernetes/issues/101493",
              "refsource": "MISC",
              "tags": [
                "Issue Tracking",
                "Mitigation",
                "Third Party Advisory"
              ],
              "url": "https://github.com/kubernetes/kubernetes/issues/101493"
            },
            {
              "name": "https://security.netapp.com/advisory/ntap-20220225-0002/",
              "refsource": "CONFIRM",
              "tags": [
                "Third Party Advisory"
              ],
              "url": "https://security.netapp.com/advisory/ntap-20220225-0002/"
            }
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      },
      "impact": {
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          "cvssV2": {
            "accessComplexity": "MEDIUM",
            "accessVector": "NETWORK",
            "authentication": "SINGLE",
            "availabilityImpact": "NONE",
            "baseScore": 3.5,
            "confidentialityImpact": "PARTIAL",
            "integrityImpact": "NONE",
            "vectorString": "AV:N/AC:M/Au:S/C:P/I:N/A:N",
            "version": "2.0"
          },
          "exploitabilityScore": 6.8,
          "impactScore": 2.9,
          "obtainAllPrivilege": false,
          "obtainOtherPrivilege": false,
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          "userInteractionRequired": false
        },
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            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
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            "baseSeverity": "LOW",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          },
          "exploitabilityScore": 1.6,
          "impactScore": 1.4
        }
      },
      "lastModifiedDate": "2022-03-29T16:35Z",
      "publishedDate": "2022-02-01T11:15Z"
    }
  }
}

CVE-2020-8562 (GCVE-0-2020-8562)

Vulnerability from cvelistv5 – Published: 2022-02-01 10:33 – Updated: 2026-06-01 21:45

Title

Bypass of Kubernetes API Server proxy TOCTOU

Summary

Severity

2.2 (Low)


                        
                          CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N

CWE

CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

Assigner

kubernetes mitre root

References

4 references

URL	Tags
https://kubernetes.io/blog/2026/05/26/reconciling…	x_refsource_MISC
https://github.com/kubernetes/kubernetes/issues/101493	x_refsource_MISC
https://groups.google.com/g/kubernetes-security-a…	x_refsource_MISC
https://security.netapp.com/advisory/ntap-2022022…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
Kubernetes	Kubernetes	Affected: 0 , < * (semver)

Date Public

2021-05-04 00:00

Credits

Javier Provecho

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T10:03:46.172Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://github.com/kubernetes/kubernetes/issues/101493"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://groups.google.com/g/kubernetes-security-announce/c/-MFX60_wdOY"
          },
          {
            "tags": [
              "x_refsource_CONFIRM",
              "x_transferred"
            ],
            "url": "https://security.netapp.com/advisory/ntap-20220225-0002/"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Kubernetes",
          "vendor": "Kubernetes",
          "versions": [
            {
              "lessThan": "*",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Javier Provecho"
        }
      ],
      "datePublic": "2021-05-04T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "As mitigations to a report from 2019 and CVE-2020-8555, Kubernetes attempts to prevent proxied connections from accessing link-local or localhost networks when making user-driven connections to Services, Pods, Nodes, or StorageClass service providers. As part of this mitigation Kubernetes does a DNS name resolution check and validates that response IPs are not in the link-local (169.254.0.0/16) or localhost (127.0.0.0/8) range. Kubernetes then performs a second DNS resolution without validation for the actual connection. If a non-standard DNS server returns different non-cached responses, a user may be able to bypass the proxy IP restriction and access private networks on the control plane."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 2.2,
            "baseSeverity": "LOW",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "HIGH",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-367",
              "description": "CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-01T21:45:40.339Z",
        "orgId": "a6081bf6-c852-4425-ad4f-a67919267565",
        "shortName": "kubernetes"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://kubernetes.io/blog/2026/05/26/reconciling-unfixed-kubernetes-cves/"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/kubernetes/kubernetes/issues/101493"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://groups.google.com/g/kubernetes-security-announce/c/-MFX60_wdOY"
        },
        {
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://security.netapp.com/advisory/ntap-20220225-0002/"
        }
      ],
      "source": {
        "defect": [
          "https://github.com/kubernetes/kubernetes/issues/101493"
        ],
        "discovery": "EXTERNAL"
      },
      "title": "Bypass of Kubernetes API Server proxy TOCTOU",
      "workarounds": [
        {
          "lang": "en",
          "value": "If this issue affects your clusters\u2019 control planes, you can use dnsmasq for name resolution and configure the min-cache-ttl and neg-ttl parameters to a low non-zero value to enforce cached replies for proxied connections"
        }
      ],
      "x_generator": {
        "engine": "Vulnogram 0.0.9"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a6081bf6-c852-4425-ad4f-a67919267565",
    "assignerShortName": "kubernetes",
    "cveId": "CVE-2020-8562",
    "datePublished": "2022-02-01T10:33:00.317Z",
    "dateReserved": "2020-02-03T00:00:00.000Z",
    "dateUpdated": "2026-06-01T21:45:40.339Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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.