CVE-2026-111766
lowmarkdown-it is a Markdown parser.
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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://github.com/markdown-it/markdown-it/commit/928bc8c11ded60181c0e7fc5aa954eec582e8e79 security-advisories@github.com
- https://github.com/markdown-it/markdown-it/commit/d99f48839d37af6fd8a2617516c43dab90755503 security-advisories@github.com
- https://github.com/markdown-it/markdown-it/releases/tag/14.3.3 security-advisories@github.com
- https://github.com/markdown-it/markdown-it/releases/tag/15.0.3 security-advisories@github.com
- https://github.com/markdown-it/markdown-it/security/advisories/GHSA-vfgh-jcmw-g37q security-advisories@github.com