MSRC_CVE-2025-66471

Vulnerability from csaf_microsoft - Published: 2025-12-02 00:00 - Updated: 2025-12-11 01:01
Summary
urllib3 Streaming API improperly handles highly compressed data

Notes

Additional Resources
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
Disclaimer
The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
To clipboard 

{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2025-66471 urllib3 Streaming API improperly handles highly compressed data - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2025/msrc_cve-2025-66471.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "urllib3 Streaming API improperly handles highly compressed data",
    "tracking": {
      "current_release_date": "2025-12-11T01:01:41.000Z",
      "generator": {
        "date": "2025-12-11T08:15:45.254Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2025-66471",
      "initial_release_date": "2025-12-02T00:00:00.000Z",
      "revision_history": [
        {
          "date": "2025-12-10T01:03:01.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        },
        {
          "date": "2025-12-11T01:01:41.000Z",
          "legacy_version": "2",
          "number": "2",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "2"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "2.0",
                "product": {
                  "name": "CBL Mariner 2.0",
                  "product_id": "17086"
                }
              },
              {
                "category": "product_version",
                "name": "3.0",
                "product": {
                  "name": "Azure Linux 3.0",
                  "product_id": "17084"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "cbl2 python-urllib3 1.26.19-2",
                "product": {
                  "name": "cbl2 python-urllib3 1.26.19-2",
                  "product_id": "2"
                }
              },
              {
                "category": "product_version_range",
                "name": "azl3 python-urllib3 2.0.7-2",
                "product": {
                  "name": "azl3 python-urllib3 2.0.7-2",
                  "product_id": "3"
                }
              }
            ],
            "category": "product_name",
            "name": "python-urllib3"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "cbl2 python-virtualenv 20.26.6-2",
                "product": {
                  "name": "cbl2 python-virtualenv 20.26.6-2",
                  "product_id": "1"
                }
              }
            ],
            "category": "product_name",
            "name": "python-virtualenv"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "azl3 tensorflow 2.16.1-9",
                "product": {
                  "name": "azl3 tensorflow 2.16.1-9",
                  "product_id": "4"
                }
              }
            ],
            "category": "product_name",
            "name": "tensorflow"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cbl2 python-urllib3 1.26.19-2 as a component of CBL Mariner 2.0",
          "product_id": "17086-2"
        },
        "product_reference": "2",
        "relates_to_product_reference": "17086"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cbl2 python-virtualenv 20.26.6-2 as a component of CBL Mariner 2.0",
          "product_id": "17086-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "17086"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 tensorflow 2.16.1-9 as a component of Azure Linux 3.0",
          "product_id": "17084-4"
        },
        "product_reference": "4",
        "relates_to_product_reference": "17084"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 python-urllib3 2.0.7-2 as a component of Azure Linux 3.0",
          "product_id": "17084-3"
        },
        "product_reference": "3",
        "relates_to_product_reference": "17084"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2025-66471",
      "cwe": {
        "id": "CWE-409",
        "name": "Improper Handling of Highly Compressed Data (Data Amplification)"
      },
      "notes": [
        {
          "category": "general",
          "text": "GitHub_M",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "known_affected": [
          "17086-2",
          "17086-1",
          "17084-4",
          "17084-3"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2025-66471 urllib3 Streaming API improperly handles highly compressed data - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2025/msrc_cve-2025-66471.json"
        }
      ],
      "remediations": [
        {
          "category": "none_available",
          "date": "2025-12-10T01:03:01.000Z",
          "details": "There is no fix available for this vulnerability as of now",
          "product_ids": [
            "17086-2"
          ]
        },
        {
          "category": "none_available",
          "date": "2025-12-10T01:03:01.000Z",
          "details": "There is no fix available for this vulnerability as of now",
          "product_ids": [
            "17086-1"
          ]
        },
        {
          "category": "none_available",
          "date": "2025-12-10T01:03:01.000Z",
          "details": "There is no fix available for this vulnerability as of now",
          "product_ids": [
            "17084-4"
          ]
        },
        {
          "category": "none_available",
          "date": "2025-12-10T01:03:01.000Z",
          "details": "There is no fix available for this vulnerability as of now",
          "product_ids": [
            "17084-3"
          ]
        }
      ],
      "title": "urllib3 Streaming API improperly handles highly compressed data"
    }
  ]
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

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.