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CVE-2026-111766GHSA-VFGH-JCMW-G37Q

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

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 15.0.3, 14.3.3
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • markdown-it markdown-it

    From 15.0.0 · fixed in 15.0.3; fixed in 14.3.3

  • markdown-itnpm

    fixed in 14.3.3

  • markdown-itnpm

    From 15.0.0 · fixed in 15.0.3

References 5

GitHub · markdown-it/markdown-it