Vulnerability-Lookup

PYSEC-2026-141

Vulnerability from pysec - Published: 2026-05-13 16:16 - Updated: 2026-05-20 09:19

Details

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.

Severity ?

5.3 (Medium)


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

Impacted products

Name	purl
urllib3	pkg:pypi/urllib3

Aliases

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "urllib3",
        "purl": "pkg:pypi/urllib3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.23"
            },
            {
              "fixed": "2.7.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.23",
        "1.24",
        "1.24.1",
        "1.24.2",
        "1.24.3",
        "1.25",
        "1.25.1",
        "1.25.10",
        "1.25.11",
        "1.25.2",
        "1.25.3",
        "1.25.4",
        "1.25.5",
        "1.25.6",
        "1.25.7",
        "1.25.8",
        "1.25.9",
        "1.26.0",
        "1.26.1",
        "1.26.10",
        "1.26.11",
        "1.26.12",
        "1.26.13",
        "1.26.14",
        "1.26.15",
        "1.26.16",
        "1.26.17",
        "1.26.18",
        "1.26.19",
        "1.26.2",
        "1.26.20",
        "1.26.3",
        "1.26.4",
        "1.26.5",
        "1.26.6",
        "1.26.7",
        "1.26.8",
        "1.26.9",
        "2.0.0",
        "2.0.0a1",
        "2.0.0a2",
        "2.0.0a3",
        "2.0.0a4",
        "2.0.1",
        "2.0.2",
        "2.0.3",
        "2.0.4",
        "2.0.5",
        "2.0.6",
        "2.0.7",
        "2.1.0",
        "2.2.0",
        "2.2.1",
        "2.2.2",
        "2.2.3",
        "2.3.0",
        "2.4.0",
        "2.5.0",
        "2.6.0",
        "2.6.1",
        "2.6.2",
        "2.6.3"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44431",
    "GHSA-qccp-gfcp-xxvc"
  ],
  "details": "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.",
  "id": "PYSEC-2026-141",
  "modified": "2026-05-20T09:19:20.983812Z",
  "published": "2026-05-13T16:16:57.150Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-44431 (GCVE-0-2026-44431)

Vulnerability from cvelistv5 – Published: 2026-05-13 15:20 – Updated: 2026-05-13 17:17

Title

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

Summary

Severity ?

8.2 (High)


                        
                          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

CWE

CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/urllib3/urllib3/security/advis…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
urllib3	urllib3	Affected: >= 1.23, < 2.7.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-44431",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-13T16:51:26.677054Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-13T17:17:07.339Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "urllib3",
          "vendor": "urllib3",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 1.23, \u003c 2.7.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 8.2,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-200",
              "description": "CWE-200: Exposure of Sensitive Information to an Unauthorized Actor",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-13T15:20:24.588Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc"
        }
      ],
      "source": {
        "advisory": "GHSA-qccp-gfcp-xxvc",
        "discovery": "UNKNOWN"
      },
      "title": "urllib3: Sensitive headers forwarded across origins in proxied low-level redirects"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-44431",
    "datePublished": "2026-05-13T15:20:24.588Z",
    "dateReserved": "2026-05-06T14:40:00.954Z",
    "dateUpdated": "2026-05-13T17:17:07.339Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

GHSA-QCCP-GFCP-XXVC

Vulnerability from github – Published: 2026-05-11 14:51 – Updated: 2026-05-14 20:35

Summary

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

Details

Impact

When following cross-origin redirects for requests made using urllib3’s high-level APIs, such as urllib3.request(), PoolManager.request(), and ProxyManager.request(), sensitive headers — Authorization, Cookie, and Proxy-Authorization (defined in Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT) — are stripped by default, as expected.

However, cross-origin redirects followed from the low-level API via ProxyManager.connection_from_url().urlopen(..., assert_same_host=False) still forward these sensitive headers.

Affected usage

Applications and libraries using urllib3 versions earlier than 2.7.0 may be affected if they allow cross-origin redirects while making requests through HTTPConnection.urlopen() instances created via ProxyManager.connection_from_url().

Remediation

Upgrade to urllib3 version 2.7.0 or later, in which sensitive headers are stripped from redirects followed by HTTPConnection.

If upgrading is not immediately possible, avoid using this low-level redirect flow for cross-origin redirects. If appropriate for your use case, switch to ProxyManager.request().

Severity ?

5.3 (Medium)


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

8.2 (High)


                  
                    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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "urllib3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.23"
            },
            {
              "fixed": "2.7.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44431"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-11T14:51:20Z",
    "nvd_published_at": "2026-05-13T16:16:57Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\nWhen following cross-origin redirects for requests made using urllib3\u2019s high-level APIs, such as `urllib3.request()`, `PoolManager.request()`, and `ProxyManager.request()`, sensitive headers \u2014 `Authorization`, `Cookie`, and `Proxy-Authorization` (defined in `Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT`) \u2014 are stripped by default, as expected.\n\nHowever, cross-origin redirects followed from the low-level API via `ProxyManager.connection_from_url().urlopen(..., assert_same_host=False)` still forward these sensitive headers.\n\n### Affected usage\n\nApplications and libraries using urllib3 versions earlier than 2.7.0 may be affected if they allow cross-origin redirects while making requests through `HTTPConnection.urlopen()` instances created via `ProxyManager.connection_from_url()`.\n\n### Remediation\n\nUpgrade to urllib3 version 2.7.0 or later, in which sensitive headers are stripped from redirects followed by `HTTPConnection`.\n\nIf upgrading is not immediately possible, avoid using this low-level redirect flow for cross-origin redirects. If appropriate for your use case, switch to `ProxyManager.request()`.",
  "id": "GHSA-qccp-gfcp-xxvc",
  "modified": "2026-05-14T20:35:49Z",
  "published": "2026-05-11T14:51:20Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44431"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/urllib3/urllib3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "urllib3: Sensitive headers forwarded across origins in proxied low-level redirects"
}

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

PYSEC-2026-141

CVE-2026-44431 (GCVE-0-2026-44431)

GHSA-QCCP-GFCP-XXVC

Impact

Affected usage

Remediation

Tags

Sightings

Nomenclature