Security advisory

{
  "id": "fe20117afc9dafbbc1261b7391042a79164614febbfe1f940abd7c726ad2763b",
  "url": "https://osv.dev/vulnerability/CVE-2021-28363",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-28363",
    "summary": "The urllib3 library 1.26.x before 1.26.4 for Python omits SSL certificate validation in some cases involving HTTPS to HTTPS proxies. The initial connection to the HTTPS proxy (if an SSLContext isn't given via proxy_config) doesn't verify the hostname of the certificate. This means certificates for different servers that still validate properly with the default urllib3 SSLContext will be silently accepted.",
    "evidence": "osv:CVE-2021-28363",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-28363",
      "aliases": [
        "CVE-2021-28363",
        "GHSA-5phf-pp7p-vc2r",
        "PYSEC-2021-59"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/urllib3/urllib3",
              "type": "GIT",
              "events": [
                {
                  "introduced": "ddb8c96bd93f3a00fe9eba142e6739533c2b7164"
                },
                {
                  "fixed": "a8913042b676c510e94fc2b097f6b514ae11a537"
                },
                {
                  "fixed": "8d65ea1ecf6e2cdc27d42124e587c1b83a3118b0"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.26.0"
                      },
                      {
                        "fixed": "1.26.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "8d65ea1ecf6e2cdc27d42124e587c1b83a3118b0"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.26.3",
            "1.26.2",
            "1.26.1",
            "1.26.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-28363.json"
          }
        }
      ],
      "modified": "2026-10-20T10:53:41.854964505Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-398330.html",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4S65ZQVZ2ODGB52IC7VJDBUK4M5INCXL/",
        "https://github.com/urllib3/urllib3/security/advisories/GHSA-5phf-pp7p-vc2r",
        "https://pypi.org/project/urllib3/1.26.4/",
        "https://security.gentoo.org/glsa/202107-36",
        "https://security.gentoo.org/glsa/202305-02",
        "https://security.netapp.com/advisory/ntap-20240621-0007/",
        "https://github.com/urllib3/urllib3/commit/8d65ea1ecf6e2cdc27d42124e587c1b83a3118b0",
        "https://github.com/urllib3/urllib3/commits/main",
        "https://www.oracle.com/security-alerts/cpuoct2021.html"
      ],
      "provider_metadata": {
        "unresolved_ranges": [
          {
            "cpes": [
              "cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*"
            ],
            "vendor_product": "fedoraproject:fedora",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "34"
                  },
                  {
                    "last_affected": "34"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          },
          {
            "cpes": [
              "cpe:2.3:a:oracle:peoplesoft_enterprise_peopletools:8.59:*:*:*:*:*:*:*"
            ],
            "vendor_product": "oracle:peoplesoft_enterprise_peopletools",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "8.59"
                  },
                  {
                    "last_affected": "8.59"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          }
        ]
      }
    },
    "related_cves": [
      {
        "value": "CVE-2021-28363",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 384512,
  "published_at": "2021-03-15T18:15:19.017+00:00"
}