Vulnerability-Lookup

ubuntu-cve-2021-33503

Vulnerability from osv_ubuntu

Published

2021-06-29 11:15

Modified

2025-07-18 16:46

Summary

Details

An issue was discovered in urllib3 before 1.26.5. When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.

Severity

7.5 (High)


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

N/A (UNKNOWN)

low

References

URL

Type

	https://ubuntu.com/security/CVE-2021-33503	REPORT
	https://github.com/advisories/GHSA-q2q7-5pp4-w6pg	REPORT
	https://github.com/urllib3/urllib3/commit/2d4a3fe…	REPORT
	https://ubuntu.com/security/notices/USN-5812-1	ADVISORY
	https://www.cve.org/CVERecord?id=CVE-2021-33503	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "python-pip-whl",
            "binary_version": "20.0.2-5ubuntu1.7"
          },
          {
            "binary_name": "python3-pip",
            "binary_version": "20.0.2-5ubuntu1.7"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "python-pip",
        "purl": "pkg:deb/ubuntu/python-pip@20.0.2-5ubuntu1.7?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "20.0.2-5ubuntu1.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "18.1-5",
        "18.1-5build1",
        "18.1-5ubuntu1",
        "20.0.2-2",
        "20.0.2-4",
        "20.0.2-5",
        "20.0.2-5ubuntu1",
        "20.0.2-5ubuntu1.1",
        "20.0.2-5ubuntu1.3",
        "20.0.2-5ubuntu1.4",
        "20.0.2-5ubuntu1.5",
        "20.0.2-5ubuntu1.6"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "python3-urllib3",
            "binary_version": "1.25.8-2ubuntu0.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "python-urllib3",
        "purl": "pkg:deb/ubuntu/python-urllib3@1.25.8-2ubuntu0.2?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.25.8-2ubuntu0.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.24.1-1ubuntu1",
        "1.24.1-1ubuntu2",
        "1.25.8-1",
        "1.25.8-2",
        "1.25.8-2ubuntu0.1"
      ]
    }
  ],
  "aliases": [],
  "details": "An issue was discovered in urllib3 before 1.26.5. When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.",
  "id": "UBUNTU-CVE-2021-33503",
  "modified": "2025-07-18T16:46:51Z",
  "published": "2021-06-29T11:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-33503"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/advisories/GHSA-q2q7-5pp4-w6pg"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/urllib3/urllib3/commit/2d4a3fee6de2fa45eb82169361918f759269b4ec"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-5812-1"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-33503"
    }
  ],
  "related": [
    "USN-5812-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "low",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2021-33503"
  ]
}

CVE-2021-33503 (GCVE-0-2021-33503)

Vulnerability from cvelistv5 – Published: 2021-06-29 10:55 – Updated: 2024-08-03 23:50

Summary

Severity

No CVSS data available.

CWE

Assigner

mitre

References

6 references

URL	Tags
https://lists.fedoraproject.org/archives/list/pac…	vendor-advisoryx_refsource_FEDORA
https://lists.fedoraproject.org/archives/list/pac…	vendor-advisoryx_refsource_FEDORA
https://security.gentoo.org/glsa/202107-36	vendor-advisoryx_refsource_GENTOO
https://www.oracle.com/security-alerts/cpuoct2021.html	x_refsource_MISC
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg	x_refsource_CONFIRM
https://github.com/urllib3/urllib3/commit/2d4a3fe…	x_refsource_CONFIRM

Show details on NVD website

JSON

To clipboard

{
  "containers": {
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      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T23:50:42.973Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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        },
        "references": [
          {
            "name": "FEDORA-2021-a6bde7ab18",
            "tags": [
              "vendor-advisory",
              "x_refsource_FEDORA",
              "x_transferred"
            ],
            "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/"
          },
          {
            "name": "FEDORA-2021-9c5f3b8aae",
            "tags": [
              "vendor-advisory",
              "x_refsource_FEDORA",
              "x_transferred"
            ],
            "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/"
          },
          {
            "name": "GLSA-202107-36",
            "tags": [
              "vendor-advisory",
              "x_refsource_GENTOO",
              "x_transferred"
            ],
            "url": "https://security.gentoo.org/glsa/202107-36"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
          },
          {
            "tags": [
              "x_refsource_CONFIRM",
              "x_transferred"
            ],
            "url": "https://github.com/advisories/GHSA-q2q7-5pp4-w6pg"
          },
          {
            "tags": [
              "x_refsource_CONFIRM",
              "x_transferred"
            ],
            "url": "https://github.com/urllib3/urllib3/commit/2d4a3fee6de2fa45eb82169361918f759269b4ec"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
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          "vendor": "n/a",
          "versions": [
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            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "An issue was discovered in urllib3 before 1.26.5. When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect."
        }
      ],
      "problemTypes": [
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          "descriptions": [
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      "providerMetadata": {
        "dateUpdated": "2021-10-20T10:42:23.000Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "name": "FEDORA-2021-a6bde7ab18",
          "tags": [
            "vendor-advisory",
            "x_refsource_FEDORA"
          ],
          "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/"
        },
        {
          "name": "FEDORA-2021-9c5f3b8aae",
          "tags": [
            "vendor-advisory",
            "x_refsource_FEDORA"
          ],
          "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/"
        },
        {
          "name": "GLSA-202107-36",
          "tags": [
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          "url": "https://security.gentoo.org/glsa/202107-36"
        },
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          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
        },
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          "url": "https://github.com/advisories/GHSA-q2q7-5pp4-w6pg"
        },
        {
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/urllib3/urllib3/commit/2d4a3fee6de2fa45eb82169361918f759269b4ec"
        }
      ],
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "cve@mitre.org",
          "ID": "CVE-2021-33503",
          "STATE": "PUBLIC"
        },
        "affects": {
          "vendor": {
            "vendor_data": [
              {
                "product": {
                  "product_data": [
                    {
                      "product_name": "n/a",
                      "version": {
                        "version_data": [
                          {
                            "version_value": "n/a"
                          }
                        ]
                      }
                    }
                  ]
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                "vendor_name": "n/a"
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        "data_format": "MITRE",
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        "description": {
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            }
          ]
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        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "eng",
                  "value": "n/a"
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        "references": {
          "reference_data": [
            {
              "name": "FEDORA-2021-a6bde7ab18",
              "refsource": "FEDORA",
              "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/"
            },
            {
              "name": "FEDORA-2021-9c5f3b8aae",
              "refsource": "FEDORA",
              "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/"
            },
            {
              "name": "GLSA-202107-36",
              "refsource": "GENTOO",
              "url": "https://security.gentoo.org/glsa/202107-36"
            },
            {
              "name": "https://www.oracle.com/security-alerts/cpuoct2021.html",
              "refsource": "MISC",
              "url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
            },
            {
              "name": "https://github.com/advisories/GHSA-q2q7-5pp4-w6pg",
              "refsource": "CONFIRM",
              "url": "https://github.com/advisories/GHSA-q2q7-5pp4-w6pg"
            },
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              "refsource": "CONFIRM",
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  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
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    "datePublished": "2021-06-29T10:55:35.000Z",
    "dateReserved": "2021-05-21T00:00:00.000Z",
    "dateUpdated": "2024-08-03T23:50:42.973Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

usn-5812-1

Vulnerability from osv_ubuntu

Published

2023-01-19 13:52

Modified

2026-02-10 04:42

Summary

python-urllib3 vulnerability

Details

It was discovered that urllib3 incorrectly handled certain characters in URLs. A remote attacker could possibly use this issue to cause urllib3 to consume resources, leading to a denial of service.

References

URL

Type

	https://ubuntu.com/security/notices/USN-5812-1	ADVISORY
	https://ubuntu.com/security/CVE-2021-33503	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2021-33503",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "low",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:20.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "python3-urllib3",
            "binary_version": "1.25.8-2ubuntu0.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "python-urllib3",
        "purl": "pkg:deb/ubuntu/python-urllib3@1.25.8-2ubuntu0.2?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.25.8-2ubuntu0.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.24.1-1ubuntu1",
        "1.24.1-1ubuntu2",
        "1.25.8-1",
        "1.25.8-2",
        "1.25.8-2ubuntu0.1"
      ]
    }
  ],
  "aliases": [],
  "details": "It was discovered that urllib3 incorrectly handled certain characters\nin URLs. A remote attacker could possibly use this issue to cause urllib3\nto consume resources, leading to a denial of service.\n",
  "id": "USN-5812-1",
  "modified": "2026-02-10T04:42:55Z",
  "published": "2023-01-19T13:52:19Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-5812-1"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-33503"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "python-urllib3 vulnerability",
  "upstream": [
    "UBUNTU-CVE-2021-33503"
  ]
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

ubuntu-cve-2021-33503

Vulnerability from osv_ubuntu

CVE-2021-33503 (GCVE-0-2021-33503)

usn-5812-1

Vulnerability from osv_ubuntu

Tags

Sightings

Nomenclature