Vulnerability-Lookup

ubuntu-cve-2021-25737

Vulnerability from osv_ubuntu

Published

2021-09-06 12:15

Modified

2025-07-14 04:45

Summary

Details

A security issue was discovered in Kubernetes where a user may be able to redirect pod traffic to private networks on a Node. Kubernetes already prevents creation of Endpoint IPs in the localhost or link-local range, but the same validation was not performed on EndpointSlice IPs.

Severity

2.7 (Low)


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

4.8 (Medium)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2021-25737	REPORT
	https://www.openwall.com/lists/oss-security/2021/…	REPORT
	https://www.cve.org/CVERecord?id=CVE-2021-25737	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "kubernetes",
        "purl": "pkg:deb/ubuntu/kubernetes@1.0?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.0"
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "kubernetes",
        "purl": "pkg:deb/ubuntu/kubernetes@1.0?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.0"
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "kubernetes",
        "purl": "pkg:deb/ubuntu/kubernetes@1.0?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.0"
      ]
    }
  ],
  "aliases": [],
  "details": "A security issue was discovered in Kubernetes where a user may be able to redirect pod traffic to private networks on a Node. Kubernetes already prevents creation of Endpoint IPs in the localhost or link-local range, but the same validation was not performed on EndpointSlice IPs.",
  "id": "UBUNTU-CVE-2021-25737",
  "modified": "2025-07-14T04:45:36Z",
  "published": "2021-09-06T12:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-25737"
    },
    {
      "type": "REPORT",
      "url": "https://www.openwall.com/lists/oss-security/2021/05/18/4"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-25737"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2021-25737"
  ],
  "withdrawn": "2025-08-28T17:00:31Z"
}

CVE-2021-25737 (GCVE-0-2021-25737)

Vulnerability from cvelistv5 – Published: 2021-09-06 11:32 – Updated: 2024-09-16 21:04

Title

Holes in EndpointSlice Validation Enable Host Network Hijack

Summary

Severity

2.7 (Low)


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

CWE

CWE-184 - Incomplete Blacklist

Assigner

kubernetes

References

3 references

URL	Tags
https://groups.google.com/g/kubernetes-security-a…	x_refsource_MISC
https://github.com/kubernetes/kubernetes/issues/102106	x_refsource_MISC
https://security.netapp.com/advisory/ntap-2021100…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
Kubernetes	Kubernetes	Affected: unspecified , ≤ 1.18.18 (custom) Affected: unspecified , ≤ 1.19.10 (custom) Affected: unspecified , ≤ 1.20.6 (custom) Affected: unspecified , ≤ 1.21.0 (custom)

Date Public

2021-05-18 00:00

Credits

John Howard

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T20:11:27.584Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://groups.google.com/g/kubernetes-security-announce/c/xAiN3924thY"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://github.com/kubernetes/kubernetes/issues/102106"
          },
          {
            "tags": [
              "x_refsource_CONFIRM",
              "x_transferred"
            ],
            "url": "https://security.netapp.com/advisory/ntap-20211004-0004/"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Kubernetes",
          "vendor": "Kubernetes",
          "versions": [
            {
              "lessThanOrEqual": "1.18.18",
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom"
            },
            {
              "lessThanOrEqual": "1.19.10",
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom"
            },
            {
              "lessThanOrEqual": "1.20.6",
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom"
            },
            {
              "lessThanOrEqual": "1.21.0",
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "John Howard"
        }
      ],
      "datePublic": "2021-05-18T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "A security issue was discovered in Kubernetes where a user may be able to redirect pod traffic to private networks on a Node. Kubernetes already prevents creation of Endpoint IPs in the localhost or link-local range, but the same validation was not performed on EndpointSlice IPs."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 2.7,
            "baseSeverity": "LOW",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "HIGH",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-184",
              "description": "CWE-184 Incomplete Blacklist",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2021-10-04T18:06:22.000Z",
        "orgId": "a6081bf6-c852-4425-ad4f-a67919267565",
        "shortName": "kubernetes"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://groups.google.com/g/kubernetes-security-announce/c/xAiN3924thY"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/kubernetes/kubernetes/issues/102106"
        },
        {
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://security.netapp.com/advisory/ntap-20211004-0004/"
        }
      ],
      "source": {
        "defect": [
          "https://github.com/kubernetes/kubernetes/issues/102106"
        ],
        "discovery": "EXTERNAL"
      },
      "title": "Holes in EndpointSlice Validation Enable Host Network Hijack",
      "x_generator": {
        "engine": "Vulnogram 0.0.9"
      },
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "security@kubernetes.io",
          "DATE_PUBLIC": "2021-05-18T19:00:00.000Z",
          "ID": "CVE-2021-25737",
          "STATE": "PUBLIC",
          "TITLE": "Holes in EndpointSlice Validation Enable Host Network Hijack"
        },
        "affects": {
          "vendor": {
            "vendor_data": [
              {
                "product": {
                  "product_data": [
                    {
                      "product_name": "Kubernetes",
                      "version": {
                        "version_data": [
                          {
                            "version_affected": "\u003c=",
                            "version_value": "1.18.18"
                          },
                          {
                            "version_affected": "\u003c=",
                            "version_value": "1.19.10"
                          },
                          {
                            "version_affected": "\u003c=",
                            "version_value": "1.20.6"
                          },
                          {
                            "version_affected": "\u003c=",
                            "version_value": "1.21.0"
                          }
                        ]
                      }
                    }
                  ]
                },
                "vendor_name": "Kubernetes"
              }
            ]
          }
        },
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            "value": "John Howard"
          }
        ],
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        "description": {
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              "value": "A security issue was discovered in Kubernetes where a user may be able to redirect pod traffic to private networks on a Node. Kubernetes already prevents creation of Endpoint IPs in the localhost or link-local range, but the same validation was not performed on EndpointSlice IPs."
            }
          ]
        },
        "generator": {
          "engine": "Vulnogram 0.0.9"
        },
        "impact": {
          "cvss": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 2.7,
            "baseSeverity": "LOW",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "HIGH",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          }
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "eng",
                  "value": "CWE-184 Incomplete Blacklist"
                }
              ]
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          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://groups.google.com/g/kubernetes-security-announce/c/xAiN3924thY",
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              "url": "https://groups.google.com/g/kubernetes-security-announce/c/xAiN3924thY"
            },
            {
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              "refsource": "MISC",
              "url": "https://github.com/kubernetes/kubernetes/issues/102106"
            },
            {
              "name": "https://security.netapp.com/advisory/ntap-20211004-0004/",
              "refsource": "CONFIRM",
              "url": "https://security.netapp.com/advisory/ntap-20211004-0004/"
            }
          ]
        },
        "source": {
          "defect": [
            "https://github.com/kubernetes/kubernetes/issues/102106"
          ],
          "discovery": "EXTERNAL"
        }
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a6081bf6-c852-4425-ad4f-a67919267565",
    "assignerShortName": "kubernetes",
    "cveId": "CVE-2021-25737",
    "datePublished": "2021-09-06T11:32:01.989Z",
    "dateReserved": "2021-01-21T00:00:00.000Z",
    "dateUpdated": "2024-09-16T21:04:34.209Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

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.

Action not permitted

ubuntu-cve-2021-25737

Vulnerability from osv_ubuntu

CVE-2021-25737 (GCVE-0-2021-25737)

Tags

Sightings

Nomenclature