Security advisory

{
  "id": "9344597a15766ebe6fd90df4b7bd2adbbae125a3e9eba40b50f20af8cbe2944e",
  "url": "https://osv.dev/vulnerability/CVE-2021-21240",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-21240",
    "summary": "httplib2 is a comprehensive HTTP client library for Python. In httplib2 before version 0.19.0, a malicious server which responds with long series of \"\\xa0\" characters in the \"www-authenticate\" header may cause Denial of Service (CPU burn while parsing header) of the httplib2 client accessing said server. This is fixed in version 0.19.0 which contains a new implementation of auth headers parsing using the pyparsing library.",
    "evidence": "osv:CVE-2021-21240",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-21240",
      "aliases": [
        "CVE-2021-21240",
        "GHSA-93xj-8mrv-444m",
        "PYSEC-2021-16"
      ],
      "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/httplib2/httplib2",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "81e80d00c2b3cb51de6019cfd28b793184d7699a"
                },
                {
                  "fixed": "bd9ee252c8f099608019709e22c0d705e98d26bc"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:httplib2_project:httplib2:*:*:*:*:*:python:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.19.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "bd9ee252c8f099608019709e22c0d705e98d26bc"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.18.1",
            "v0.18.0",
            "v0.17.4",
            "v0.17.3",
            "v0.17.2",
            "v0.17.1",
            "v0.17.0",
            "v0.16.0",
            "v0.15.0",
            "v0.14.0",
            "v0.13.1",
            "v0.13.0",
            "v0.12.3",
            "v0.12.0",
            "v0.11.3",
            "v0.11.2",
            "v0.11.1",
            "v0.11.0",
            "v0.10.3",
            "v0.10.1",
            "0.9.2",
            "v0.9.1",
            "0.9.1",
            "v0.9",
            "0.9"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-21240.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:27.774127796Z",
      "provider": "osv",
      "references": [
        "https://github.com/httplib2/httplib2/commit/bd9ee252c8f099608019709e22c0d705e98d26bc",
        "https://github.com/httplib2/httplib2/pull/182",
        "https://pypi.org/project/httplib2",
        "https://github.com/httplib2/httplib2/security/advisories/GHSA-93xj-8mrv-444m"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-21240",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 385381,
  "published_at": "2021-02-08T20:15:12.197+00:00"
}