---
id: CVE-2025-46656
aliases:
  - GHSA-7mpr-5m44-h73r
  - PYSEC-2026-1604
title: >-
  markdownify allows large headline prefixes such as <h9999999>, which causes
  memory consumption
summary: >-
  markdownify allows large headline prefixes such as <h9999999>, which causes
  memory consumption
severity: low
cvss: 2.9
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L'
vendor: markdownify
product: markdownify
ecosystem: pip
affected:
  - markdownify < 0.14.1
patched:
  - markdownify 0.14.1
published: '2025-04-27'
updated: '2026-07-07'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-7mpr-5m44-h73r'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-46656'
  - url: 'https://github.com/matthewwithanm/python-markdownify/issues/143'
  - url: >-
      https://github.com/matthewwithanm/python-markdownify/commit/959561879693bf4a576f99c6733b50b01186aa08
  - url: 'https://github.com/matthewwithanm/python-markdownify'
  - url: >-
      https://github.com/matthewwithanm/python-markdownify/compare/0.14.0...0.14.1
tags:
  - osv
  - pip
epss: 0.0022
epssPercentile: 0.11195
ingestedAt: '2026-07-08T18:25:47.046Z'
---

## Overview

python-markdownify (aka markdownify) before 0.14.1 allows large headline prefixes such as <h9999999> in addition to <h1> through <h6>. This causes memory consumption.

## Affected packages

- `markdownify < 0.14.1`

## Remediation

Upgrade to a patched release:

- `markdownify 0.14.1`