---
id: CVE-2026-115348
title: Mistune before 3.3.0 Quadratic-Time DoS via parse_link_text
summary: >-
  Mistune from 3.0.0 before 3.3.0 contains an algorithmic complexity
  vulnerability in the inline link parser's parse_link_text function that allows
  unauthenticated attackers to exhaust CPU with unbalanced brackets. Attackers
  can submit Mar…
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
vendor: lepture
product: mistune
affected:
  - mistune >= 3.0.0 < 3.3.0
published: '2026-10-22'
updated: '2026-10-22'
sourceUpdated: '2026-10-22T19:13:25.416Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-115348'
references:
  - url: 'https://github.com/lepture/mistune/security/advisories/GHSA-x2gr-6qf2-fc9x'
    label: GitHub Security Advisory (GHSA-x2gr-6qf2-fc9x)
  - url: >-
      https://www.vulncheck.com/advisories/mistune-before-3.3.0-quadratic-time-dos-via-parse-link-text
    label: >-
      VulnCheck Advisory: Mistune before 3.3.0 Quadratic-Time DoS via
      parse_link_text
tags:
  - cve.org
ingestedAt: '2026-10-22T22:00:50.395Z'
---

## Overview

Mistune from 3.0.0 before 3.3.0 contains an algorithmic complexity vulnerability in the inline link parser's parse_link_text function that allows unauthenticated attackers to exhaust CPU with unbalanced brackets. Attackers can submit Markdown containing many unbalanced '[' or '![' characters, forcing repeated unbounded forward scans and tying up worker processes for minutes.

## Affected

- `mistune >= 3.0.0 < 3.3.0`

## Remediation

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