← CVE Intelligence

CVE-2026-111766

markdown-it: Quadratic-time denial of service in inline HTML parsing with html enabled PUBLISHED

Description (CNA)

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 (CNA)

Vendor / productVersions
markdown-it / markdown-itaffected >= 15.0.0, < 15.0.3; affected < 14.3.3

CWE

CWE-400, CWE-407

References