{"id":"CVE-2026-111766","summary":"markdown-it: Quadratic-time denial of service in inline HTML parsing with html enabled","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.","aliases":["GHSA-vfgh-jcmw-g37q"],"modified":"2026-10-21T02:55:48.900458294Z","published":"2026-10-19T19:47:46.488Z","database_specific":{"cwe_ids":["CWE-400","CWE-407"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/111xxx/CVE-2026-111766.json","unresolved_ranges":[{"extracted_events":[{"source":"AFFECTED_FIELD","strategy":"StringRangeExpression","range":[{"introduced":"15.0.0"},{"fixed":"15.0.3"},{"fixed":"14.3.3"}]}]},{"extracted_events":[{"range":[{"fixed":"14.3.3"},{"fixed":"14.3.3"}],"source":"DESCRIPTION"}]}],"cna_assigner":"GitHub_M"},"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"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/markdown-it/markdown-it","events":[{"introduced":"0"},{"fixed":"928bc8c11ded60181c0e7fc5aa954eec582e8e79"},{"fixed":"d99f48839d37af6fd8a2617516c43dab90755503"},{"fixed":"d372f0d8a68bef0b0acaa68868ce8ae8ba85b384"},{"fixed":"a8c00d474ec9b304fad9b71c16d6fa8b4909279e"}],"database_specific":{"extracted_events":[{"range":[{"fixed":"928bc8c11ded60181c0e7fc5aa954eec582e8e79"}],"source":"REFERENCES_COMMIT"},{"source":"REFERENCES_COMMIT","range":[{"fixed":"d99f48839d37af6fd8a2617516c43dab90755503"}]},{"original_tag":"14.3.3","range":[{"fixed":"d372f0d8a68bef0b0acaa68868ce8ae8ba85b384"}],"source":"REFERENCES_TAG"},{"range":[{"fixed":"a8c00d474ec9b304fad9b71c16d6fa8b4909279e"}],"source":"REFERENCES_TAG","original_tag":"15.0.3"}]}}],"versions":["14.3.2","15.0.2","14.3.1","15.0.1","15.0.0","14.3.0","14.2.0","14.1.1","14.1.0","14.0.0","13.0.2","13.0.1","13.0.0","12.3.2","12.3.1","12.3.0","12.2.0","12.1.0","12.0.6","12.0.5","12.0.4","12.0.3","12.0.2","12.0.1","12.0.0","11.0.1","11.0.0","10.0.0","9.1.0","9.0.1","9.0.0","8.4.2","8.4.1","8.4.0","8.3.2","8.3.1","8.3.0","8.2.2","8.2.1","8.2.0","8.1.0","8.0.1","8.0.0","7.0.1","7.0.0","6.1.1","6.1.0","6.0.5","6.0.4","6.0.3","6.0.2","6.0.1","6.0.0","5.1.0","5.0.3","5.0.2","5.0.1","5.0.0","4.4.0","4.3.1","4.3.0","4.2.2","4.2.1","4.2.0","4.1.2","4.1.1","4.1.0","4.0.3","4.0.2","4.0.1","4.0.0","3.1.0","3.0.7","3.0.6","3.0.5","3.0.4","3.0.3","3.0.2","3.0.1","3.0.0","2.2.1","2.2.0","2.1.3","2.1.2","2.1.1","2.1.0","2.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-111766.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}