urllib3: Sensitive headers forwarded across origins in proxied low-level redirects

{
  "id": "e1ca1f65cf678fd70e18b0096a2347cfc6f43e3f8e787f212dbf714d1f7538e0",
  "url": "https://osv.dev/vulnerability/CVE-2026-44431",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "urllib3: Sensitive headers forwarded across origins in proxied low-level redirects",
    "summary": "urllib3 is an HTTP client library for Python. From 1.23 to before 2.7.0, cross-origin redirects followed from the low-level API via ProxyManager.connection_from_url().urlopen(..., assert_same_host=False) still forward these sensitive headers. This vulnerability is fixed in 2.7.0.",
    "evidence": "osv:CVE-2026-44431",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-44431",
      "aliases": [
        "CVE-2026-44431",
        "GHSA-qccp-gfcp-xxvc",
        "PYSEC-2026-141"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/urllib3/urllib3",
              "type": "GIT",
              "events": [
                {
                  "introduced": "7c216f433e39e184b84cbfa49e41135a89e4baa0"
                },
                {
                  "fixed": "9a950b92d999f906b6020bb2d1076ee56cddd5d2"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "1.23"
                      },
                      {
                        "fixed": "2.7.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "cpe": "cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.23"
                      },
                      {
                        "fixed": "2.7.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44431.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:50.167115001Z",
      "provider": "osv",
      "references": [
        "https://lists.debian.org/debian-lts-announce/2026/06/msg00040.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44431.json",
        "https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-44431"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-200"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44431.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-44431",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 518422,
  "published_at": "2026-05-13T15:20:24.588+00:00"
}