Security advisory

{
  "id": "0f642bd385ce72cb055edc0f3a559c32b84df7f962bcfa2bcd5458966d88857b",
  "url": "https://osv.dev/vulnerability/CVE-2020-7212",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2020-7212",
    "summary": "The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2).",
    "evidence": "osv:CVE-2020-7212",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2020-7212",
      "aliases": [
        "CVE-2020-7212",
        "GHSA-hmv2-79q8-fv6g",
        "PYSEC-2020-149"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/urllib3/urllib3",
              "type": "GIT",
              "events": [
                {
                  "introduced": "49eea8082ab34094d0c53f1d26e5c588d5372d74"
                },
                {
                  "last_affected": "37ba61a8b8120cbd866d057eaa3936f4b140dee0"
                },
                {
                  "fixed": "a74c9cfbaed9f811e7563cfc3dce894928e0221a"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.25.2"
                      },
                      {
                        "last_affected": "1.25.7"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "a74c9cfbaed9f811e7563cfc3dce894928e0221a"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.25.7",
            "1.25.6",
            "1.25.5",
            "1.25.4",
            "1.25.3",
            "1.25.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-7212.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:23.662174666Z",
      "provider": "osv",
      "references": [
        "https://github.com/urllib3/urllib3/blob/master/CHANGES.rst",
        "https://pypi.org/project/urllib3/1.25.8/",
        "https://github.com/urllib3/urllib3/commit/a74c9cfbaed9f811e7563cfc3dce894928e0221a"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2020-7212",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 385272,
  "published_at": "2020-03-06T20:15:12.707+00:00"
}