---
title: "CVE-2026-111758: markdown-it - Denial of Service"
description: "markdown-it 14.1.0 < versions < 14.3.3 and 15.0.0 < versions < 15.0.3 contain a denial of service caused by inefficient handling of unclosed link reference definitions in src/rules_block/reference.ts, letting attackers cause high CPU usage, exploit requires no special options."
url: https://panop.io/threat-heartbeat/CVE-2026-111758/
---

# CVE-2026-111758 markdown-it - Denial of Service

markdown-it 14.1.0 < versions < 14.3.3 and 15.0.0 < versions < 15.0.3 contain a denial of service caused by inefficient handling of unclosed link reference definitions in src/rules\_block/reference.ts, letting attackers cause high CPU usage, exploit requires no special options.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-111758)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Published

20 October 2026

Updated

21 October 2026

Weakness

[CWE-400](https://cwe.mitre.org/data/definitions/400.html)

## Vendor fix

Update to versions 14.3.3 or 15.0.3 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-111758](https://nvd.nist.gov/vuln/detail/CVE-2026-111758)
- [https://github.com/markdown-it/markdown-it/commit/48fbc465812c440020c663f040ab22deaf8f1eca](https://github.com/markdown-it/markdown-it/commit/48fbc465812c440020c663f040ab22deaf8f1eca)
- [https://github.com/markdown-it/markdown-it/commit/d99f48839d37af6fd8a2617516c43dab90755503](https://github.com/markdown-it/markdown-it/commit/d99f48839d37af6fd8a2617516c43dab90755503)
- [https://github.com/markdown-it/markdown-it/releases/tag/14.3.3](https://github.com/markdown-it/markdown-it/releases/tag/14.3.3)
- [https://github.com/markdown-it/markdown-it/releases/tag/15.0.3](https://github.com/markdown-it/markdown-it/releases/tag/15.0.3)
- [https://github.com/markdown-it/markdown-it/security/advisories/GHSA-gfr2-rv44-r23c](https://github.com/markdown-it/markdown-it/security/advisories/GHSA-gfr2-rv44-r23c)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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