{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "15.0.0"
                  },
                  {
                    "fixed": "15.0.3"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              },
              {
                "range": [
                  {
                    "introduced": "0"
                  },
                  {
                    "fixed": "14.3.3"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              },
              {
                "range": [
                  {
                    "fixed": "928bc8c11ded60181c0e7fc5aa954eec582e8e79"
                  }
                ],
                "source": "REFERENCES_COMMIT"
              },
              {
                "range": [
                  {
                    "fixed": "d99f48839d37af6fd8a2617516c43dab90755503"
                  }
                ],
                "source": "REFERENCES_COMMIT"
              },
              {
                "original_tag": "14.3.3",
                "range": [
                  {
                    "fixed": "d372f0d8a68bef0b0acaa68868ce8ae8ba85b384"
                  }
                ],
                "source": "REFERENCES_TAG"
              },
              {
                "original_tag": "15.0.3",
                "range": [
                  {
                    "fixed": "a8c00d474ec9b304fad9b71c16d6fa8b4909279e"
                  }
                ],
                "source": "REFERENCES_TAG"
              }
            ]
          },
          "events": [
            {
              "introduced": "157b33bc13649aebecf9ab9b3b8c85ae645abb5a"
            },
            {
              "fixed": "a8c00d474ec9b304fad9b71c16d6fa8b4909279e"
            },
            {
              "introduced": "0"
            },
            {
              "fixed": "d372f0d8a68bef0b0acaa68868ce8ae8ba85b384"
            },
            {
              "fixed": "928bc8c11ded60181c0e7fc5aa954eec582e8e79"
            },
            {
              "fixed": "d99f48839d37af6fd8a2617516c43dab90755503"
            }
          ],
          "repo": "https://github.com/markdown-it/markdown-it",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-vfgh-jcmw-g37q"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-400",
      "CWE-407"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/111xxx/CVE-2026-111766.json"
  },
  "details": "markdown-it is a Markdown parser. Prior to 14.3.3 and 15.0.3, when the html option or commonmark preset is enabled and the constructs occur inside a paragraph, attacker-controlled Markdown containing repeated unterminated inline HTML comments, processing instructions, declarations, or CDATA sections reaches src/rules_inline/html_inline.ts. Its HTML_TAG_RE match searches the remaining suffix for the appropriate terminator; when no terminator is present, parsing advances to the next opener and repeats the match over overlapping input, causing quadratic processing and denial of service through event-loop blocking or an unresponsive browser main thread. HTML blocks and the default HTML-disabled configuration are not affected by these payloads. This issue is fixed in versions 14.3.3 and 15.0.3.",
  "id": "CVE-2026-111766",
  "modified": "2026-10-22T02:31:02.057034460Z",
  "published": "2026-10-19T19:47:46.488Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/111xxx/CVE-2026-111766.json"
    },
    {
      "type": "FIX",
      "url": "https://github.com/markdown-it/markdown-it/commit/928bc8c11ded60181c0e7fc5aa954eec582e8e79"
    },
    {
      "type": "FIX",
      "url": "https://github.com/markdown-it/markdown-it/commit/d99f48839d37af6fd8a2617516c43dab90755503"
    },
    {
      "type": "WEB",
      "url": "https://github.com/markdown-it/markdown-it/releases/tag/14.3.3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/markdown-it/markdown-it/releases/tag/15.0.3"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/markdown-it/markdown-it/security/advisories/GHSA-vfgh-jcmw-g37q"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-111766"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "markdown-it: Quadratic-time denial of service in inline HTML parsing with html enabled"
}