---
id: CVE-2026-111758
title: >-
  markdown-it: Quadratic-time rendering of a single multi-line link reference
  definition with default options (regression since 14.0)
summary: >-
  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 wi…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-400
  - CWE-407
  - CWE-1046
vendor: markdown-it
product: markdown-it
affected:
  - 'markdown-it >= 14.1.0, < 14.3.3'
  - 'markdown-it >= 15.0.0, < 15.0.3'
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-28T16:39:57.942731Z'
exploitAvailable: true
published: '2026-10-20'
updated: '2026-10-28'
sourceUpdated: '2026-10-28T16:40:33.483Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-111758'
references:
  - url: >-
      https://github.com/markdown-it/markdown-it/security/advisories/GHSA-gfr2-rv44-r23c
    label: >-
      https://github.com/markdown-it/markdown-it/security/advisories/GHSA-gfr2-rv44-r23c
  - url: >-
      https://github.com/markdown-it/markdown-it/commit/48fbc465812c440020c663f040ab22deaf8f1eca
    label: >-
      https://github.com/markdown-it/markdown-it/commit/48fbc465812c440020c663f040ab22deaf8f1eca
  - url: >-
      https://github.com/markdown-it/markdown-it/commit/d99f48839d37af6fd8a2617516c43dab90755503
    label: >-
      https://github.com/markdown-it/markdown-it/commit/d99f48839d37af6fd8a2617516c43dab90755503
  - url: 'https://github.com/markdown-it/markdown-it/releases/tag/14.3.3'
    label: 'https://github.com/markdown-it/markdown-it/releases/tag/14.3.3'
  - url: 'https://github.com/markdown-it/markdown-it/releases/tag/15.0.3'
    label: 'https://github.com/markdown-it/markdown-it/releases/tag/15.0.3'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-111758.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-111758'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2556455'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-111758'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-111758'
  - url: 'https://github.com/advisories/GHSA-gfr2-rv44-r23c'
tags:
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
  - ghsa
  - npm
epss: 0.00455
epssPercentile: 0.39405
aliases:
  - GHSA-gfr2-rv44-r23c
ecosystem: npm
patched:
  - markdown-it 14.3.3
  - markdown-it 15.0.3
ingestedAt: '2026-10-20T21:19:21.139Z'
---

## Overview

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.

## Affected

- `markdown-it >= 14.1.0, < 14.3.3`
- `markdown-it >= 15.0.0, < 15.0.3`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-111758)

Affected packages:

- `markdown-it >= 14.1.0, < 14.3.3`
- `markdown-it >= 15.0.0, < 15.0.3`

Patched in:

- `markdown-it 14.3.3`
- `markdown-it 15.0.3`

Source: https://github.com/advisories/GHSA-gfr2-rv44-r23c

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Build of Podman Desktop, Red Hat Ceph Storage 9, Red Hat Developer Hub, Red Hat Hardened Images, Red Hat OpenShift AI (RHOAI), Red Hat OpenShift Dev Spaces, … · no fix planned: Red Hat Ceph Storage 9, Red Hat Build of Podman Desktop, Red Hat Developer Hub, Red Hat Hardened Images, … · updated 2026-10-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-111758.json)