{"api_version":"1","generated_at":"2026-10-21T00:47:16+00:00","cve":"CVE-2026-111766","urls":{"html":"https://cve.report/CVE-2026-111766","api":"https://cve.report/api/cve/CVE-2026-111766.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-111766","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-111766"},"summary":{"title":"markdown-it: Quadratic-time denial of service in inline HTML parsing with html enabled","description":"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.","state":"PUBLISHED","assigner":"GitHub_M","published_at":"2026-10-19 20:17:52","updated_at":"2026-10-19 20:17:52"},"problem_types":["CWE-400","CWE-407","CWE-400 CWE-400: Uncontrolled Resource Consumption","CWE-407 CWE-407: Inefficient Algorithmic Complexity"],"metrics":[{"version":"3.1","source":"security-advisories@github.com","type":"Secondary","score":"3.7","severity":"LOW","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L","data":{"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"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"3.7","severity":"LOW","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L","data":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":3.7,"baseSeverity":"LOW","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L","version":"3.1"}}],"references":[{"url":"https://github.com/markdown-it/markdown-it/releases/tag/15.0.3","name":"https://github.com/markdown-it/markdown-it/releases/tag/15.0.3","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/markdown-it/markdown-it/releases/tag/14.3.3","name":"https://github.com/markdown-it/markdown-it/releases/tag/14.3.3","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/markdown-it/markdown-it/commit/d99f48839d37af6fd8a2617516c43dab90755503","name":"https://github.com/markdown-it/markdown-it/commit/d99f48839d37af6fd8a2617516c43dab90755503","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/markdown-it/markdown-it/security/advisories/GHSA-vfgh-jcmw-g37q","name":"https://github.com/markdown-it/markdown-it/security/advisories/GHSA-vfgh-jcmw-g37q","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/markdown-it/markdown-it/commit/928bc8c11ded60181c0e7fc5aa954eec582e8e79","name":"https://github.com/markdown-it/markdown-it/commit/928bc8c11ded60181c0e7fc5aa954eec582e8e79","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-111766","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-111766","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"markdown-it","product":"markdown-it","version":"affected >= 15.0.0, < 15.0.3","platforms":[]},{"source":"CNA","vendor":"markdown-it","product":"markdown-it","version":"affected < 14.3.3","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"product":"markdown-it","vendor":"markdown-it","versions":[{"status":"affected","version":">= 15.0.0, < 15.0.3"},{"status":"affected","version":"< 14.3.3"}]}],"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."}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":3.7,"baseSeverity":"LOW","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-400","description":"CWE-400: Uncontrolled Resource Consumption","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-407","description":"CWE-407: Inefficient Algorithmic Complexity","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-10-19T19:47:46.488Z","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M"},"references":[{"name":"https://github.com/markdown-it/markdown-it/security/advisories/GHSA-vfgh-jcmw-g37q","tags":["x_refsource_CONFIRM"],"url":"https://github.com/markdown-it/markdown-it/security/advisories/GHSA-vfgh-jcmw-g37q"},{"name":"https://github.com/markdown-it/markdown-it/commit/928bc8c11ded60181c0e7fc5aa954eec582e8e79","tags":["x_refsource_MISC"],"url":"https://github.com/markdown-it/markdown-it/commit/928bc8c11ded60181c0e7fc5aa954eec582e8e79"},{"name":"https://github.com/markdown-it/markdown-it/commit/d99f48839d37af6fd8a2617516c43dab90755503","tags":["x_refsource_MISC"],"url":"https://github.com/markdown-it/markdown-it/commit/d99f48839d37af6fd8a2617516c43dab90755503"},{"name":"https://github.com/markdown-it/markdown-it/releases/tag/14.3.3","tags":["x_refsource_MISC"],"url":"https://github.com/markdown-it/markdown-it/releases/tag/14.3.3"},{"name":"https://github.com/markdown-it/markdown-it/releases/tag/15.0.3","tags":["x_refsource_MISC"],"url":"https://github.com/markdown-it/markdown-it/releases/tag/15.0.3"}],"source":{"advisory":"GHSA-vfgh-jcmw-g37q","discovery":"UNKNOWN"},"title":"markdown-it: Quadratic-time denial of service in inline HTML parsing with html enabled"}},"cveMetadata":{"assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","assignerShortName":"GitHub_M","cveId":"CVE-2026-111766","datePublished":"2026-10-19T19:47:46.488Z","dateReserved":"2026-10-16T17:52:09.082Z","dateUpdated":"2026-10-19T19:47:46.488Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-19 20:17:52","lastModifiedDate":"2026-10-19 20:17:52","problem_types":["CWE-400","CWE-407","CWE-400 CWE-400: Uncontrolled Resource Consumption","CWE-407 CWE-407: Inefficient Algorithmic Complexity"],"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}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"111766","Ordinal":"1","Title":"markdown-it: Quadratic-time denial of service in inline HTML par","CVE":"CVE-2026-111766","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"111766","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"markdown-it: Quadratic-time denial of service in inline HTML par"}]}}}