CVE-2023-43804: Urllib3 `Cookie` HTTP Header Isn't Stripped Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-v845-jxx5-vc9f",
  "modified" : "2025-11-04T16:45:50Z",
  "published" : "2023-10-02T23:27:05Z",
  "aliases" : [ "CVE-2023-43804" ],
  "summary" : "`Cookie` HTTP header isn't stripped on cross-origin redirects",
  "details" : "urllib3 doesn't treat the `Cookie` HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a `Cookie` header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.\n\nUsers **must** handle redirects themselves instead of relying on urllib3's automatic redirects to achieve safe processing of the `Cookie` header, thus we decided to strip the header by default in order to further protect users who aren't using the correct approach.\n\n## Affected usages\n\nWe believe the number of usages affected by this advisory is low. It requires all of the following to be true to be exploited:\n\n* Using an affected version of urllib3 (patched in v1.26.17 and v2.0.6)\n* Using the `Cookie` header on requests, which is mostly typical for impersonating a browser.\n* Not disabling HTTP redirects\n* Either not using HTTPS or for the origin server to redirect to a malicious origin.\n\n## Remediation\n\n* Upgrading to at least urllib3 v1.26.17 or v2.0.6\n* Disabling HTTP redirects using `redirects=False` when sending requests.\n* Not using the `Cookie` header.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "urllib3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.0"
      }, {
        "fixed" : "2.0.6"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "urllib3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.26.17"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-43804"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/urllib3/urllib3/commit/01220354d389cd05474713f8c982d05c9b17aafb"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/urllib3/urllib3/commit/644124ecd0b6e417c527191f866daa05a5a2056d"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/urllib3/PYSEC-2023-192.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/urllib3/urllib3"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2023/10/msg00012.html"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2024/12/msg00020.html"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5F5CUBAN5XMEBVBZPHFITBLMJV5FIJJ5"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/I3PR7C6RJ6JUBQKIJ644DMIJSUP36VDY"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NDAGZXYJ7H2G3SB47M453VQVNAWKAEJJ"
  }, {
    "type" : "WEB",
    "url" : "https://security.netapp.com/advisory/ntap-20241213-0007"
  }, {
    "type" : "WEB",
    "url" : "https://www.vicarius.io/vsociety/posts/cve-2023-43804-urllib3-vulnerability-3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-10-02T23:27:05Z",
    "nvd_published_at" : "2023-10-04T17:15:10Z"
  }
}