CVE-2026-111758
HIGH
CVSS 7.5
Published: 2026-10-20
Modified: 2026-10-22
Tenable Plugin
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Threat Intelligence Pending
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Description
markdown-it is a Markdown parser. From versions 14.1.0 to before 14.3.3, and 15.0.0 to before 15.0.3, a link reference definition whose label or title is never closed is O(n²) with default options. Continuation lines are pulled lazily with str += lineContent in src/rules_block/reference.ts, and the subsequent charCodeAt and slice calls flatten the V8 cons-string, copying everything collected so far; this runs before the rule decides the definition is invalid. No options are required to trigger it. This issue has been patched in versions 14.3.3 and 15.0.3.
Quick Facts
| CVE ID | CVE-2026-111758 |
| CVSS Score | 7.5 |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| Published | 2026-10-20 |
| Exploited | No |
| CISA KEV | No |
| PoC | Not public |
References
- https://github.com/markdown-it/markdown-it/commit/48fbc46581…
- https://github.com/markdown-it/markdown-it/commit/d99f48839d…
- https://github.com/markdown-it/markdown-it/releases/tag/14.3…
- https://github.com/markdown-it/markdown-it/releases/tag/15.0…
- https://github.com/markdown-it/markdown-it/security/advisori…