---
id: CVE-2026-76098
title: Mistune is a Python Markdown parser with renderers and plugins
summary: >-
  Mistune is a Python Markdown parser with renderers and plugins. Versions 3.3.0
  through 3.3.2 are vulnerable to DoS through deeply nested tokens. HTML
  rendering creates deeply nested emphasis tokens from consecutive asterisk
  characters, a…
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'
cwe:
  - CWE-674
  - CWE-770
vendor: mistune
product: mistune
affected:
  - 'mistune >= 3.3.0, < 3.3.3'
patched:
  - mistune 3.3.3
published: '2026-08-24'
updated: '2026-10-12'
sourceUpdated: '2026-10-12T15:10:00.207'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-76098'
references:
  - url: 'https://github.com/lepture/mistune/commit/0938fb7'
    label: security-advisories@github.com
  - url: 'https://github.com/lepture/mistune/security/advisories/GHSA-6m44-fpc8-c3rq'
    label: security-advisories@github.com
  - url: 'https://github.com/lepture/mistune/security/advisories/GHSA-6m44-fpc8-c3rq'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-76098'
  - url: >-
      https://github.com/lepture/mistune/commit/0938fb781d0aded99de801b340ec1f8debeae5b2
  - url: 'https://github.com/lepture/mistune/releases/tag/v3.3.3'
  - url: 'https://github.com/advisories/GHSA-6m44-fpc8-c3rq'
  - url: 'https://github.com/lepture/mistune'
  - url: 'https://pypi.org/project/mistune'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-76098.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-76098'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2523100'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-76098'
  - url: 'https://access.redhat.com/errata/RHSA-2026:84734'
tags:
  - nvd
  - ghsa
  - pip
  - osv
  - csaf
  - vex
  - red-hat
epss: 0.00488
epssPercentile: 0.41803
aliases:
  - GHSA-6m44-fpc8-c3rq
  - PYSEC-2026-3863
ecosystem: pip
ingestedAt: '2026-09-02T15:46:29.449Z'
---

## Overview

Mistune is a Python Markdown parser with renderers and plugins. Versions 3.3.0 through 3.3.2 are vulnerable to DoS through deeply nested tokens. HTML rendering creates deeply nested emphasis tokens from consecutive asterisk characters, and recursive rendering in HTMLRenderer.render_token() can exceed Python's recursion limit and raise RecursionError, allowing crafted Markdown to crash a parsing process. This issue is fixed in version 3.3.3

## Remediation

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

## Package advisory (CVE-2026-76098)

Affected packages:

- `mistune >= 3.3.0, < 3.3.3`

Patched in:

- `mistune 3.3.3`

Source: https://github.com/advisories/GHSA-6m44-fpc8-c3rq

## Vendor advisories

- **RHSA-2026:84734** · Red Hat · fixed in: Red Hat OpenShift AI 3.4 · released 2026-10-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:84734)
- **Red Hat VEX** · Important · affected: Red Hat OpenShift AI (RHOAI) · no fix planned: Red Hat OpenShift AI (RHOAI) · updated 2026-10-19 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-76098.json)