{"id":"CVE-2026-111766","sourceIdentifier":"security-advisories@github.com","published":"2026-10-19T20:17:52.247","lastModified":"2026-10-26T18:17:36.273","vulnStatus":"Awaiting Analysis","cveTags":[],"descriptions":[{"lang":"en","value":"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."}],"affected":[{"source":"security-advisories@github.com","affectedData":[{"vendor":"markdown-it","product":"markdown-it","versions":[{"version":">= 15.0.0, < 15.0.3","status":"affected"},{"version":"< 14.3.3","status":"affected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L","baseScore":3.7,"baseSeverity":"LOW","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"LOW"},"exploitabilityScore":2.2,"impactScore":1.4}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-10-26T17:29:30.362422Z","id":"CVE-2026-111766","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Secondary","description":[{"lang":"en","value":"CWE-400"},{"lang":"en","value":"CWE-407"}]}],"references":[{"url":"https://github.com/markdown-it/markdown-it/commit/928bc8c11ded60181c0e7fc5aa954eec582e8e79","source":"security-advisories@github.com"},{"url":"https://github.com/markdown-it/markdown-it/commit/d99f48839d37af6fd8a2617516c43dab90755503","source":"security-advisories@github.com"},{"url":"https://github.com/markdown-it/markdown-it/releases/tag/14.3.3","source":"security-advisories@github.com"},{"url":"https://github.com/markdown-it/markdown-it/releases/tag/15.0.3","source":"security-advisories@github.com"},{"url":"https://github.com/markdown-it/markdown-it/security/advisories/GHSA-vfgh-jcmw-g37q","source":"security-advisories@github.com"}]}