Security advisory

{
  "id": "333d39f61daf70976b32dbff9a67c5cd93c40a928aa992e3ab9ce4ffb10fc070",
  "url": "https://osv.dev/vulnerability/CVE-2021-40978",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-40978",
    "summary": "The mkdocs 1.2.2 built-in dev-server allows directory traversal using the port 8000, enabling remote exploitation to obtain :sensitive information. NOTE: the vendor has disputed this as described in https://github.com/mkdocs/mkdocs/issues/2601.] and https://github.com/nisdn/CVE-2021-40978/issues/1",
    "evidence": "osv:CVE-2021-40978",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-40978",
      "aliases": [
        "CVE-2021-40978",
        "GHSA-qh9q-34h6-hcv9",
        "PYSEC-2021-878"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mkdocs/mkdocs",
              "type": "GIT",
              "events": [
                {
                  "introduced": "52ed45a58cbec0d9860d13e5ac123d6fd14aeca6"
                },
                {
                  "last_affected": "52ed45a58cbec0d9860d13e5ac123d6fd14aeca6"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:mkdocs:mkdocs:1.2.2:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.2.2"
                      },
                      {
                        "last_affected": "1.2.2"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.2.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-40978.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:57.600427508Z",
      "provider": "osv",
      "references": [
        "https://github.com/mkdocs/mkdocs",
        "https://github.com/mkdocs/mkdocs/issues/2601",
        "https://github.com/nisdn/CVE-2021-40978/issues/1",
        "https://github.com/nisdn/CVE-2021-40978"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-40978",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 386546,
  "published_at": "2021-10-07T14:15:08.28+00:00"
}