---
id: CVE-2026-8445
title: >-
  justhtml versions <= 1.11.0 (fixed in 1.12.0) do not sufficiently escape
  HTML-significant characters (angle brackets) in text nodes when converting a
  parsed document to Markdown via to_markdown()
summary: >-
  justhtml versions <= 1.11.0 (fixed in 1.12.0) do not sufficiently escape
  HTML-significant characters (angle brackets) in text nodes when converting a
  parsed document to Markdown via to_markdown(). While a small set of Markdown
  metacharac…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-79
vendor: justhtml
product: justhtml
affected:
  - justhtml < 1.12.0
patched:
  - justhtml 1.12.0
published: '2026-08-23'
updated: '2026-10-12'
sourceUpdated: '2026-10-12T16:10:00.220'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-8445'
references:
  - url: >-
      https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-3rcm-vjrc-p45j
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/justhtml-before-sanitizer-bypass-via-markdown
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-3rcm-vjrc-p45j
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://github.com/EmilStenstrom/justhtml'
tags:
  - nvd
  - osv
  - pip
epss: 0.00635
epssPercentile: 0.50221
aliases:
  - GHSA-3rcm-vjrc-p45j
ecosystem: pip
ingestedAt: '2026-08-24T19:25:43.962Z'
---

## Overview

justhtml versions <= 1.11.0 (fixed in 1.12.0) do not sufficiently escape HTML-significant characters (angle brackets) in text nodes when converting a parsed document to Markdown via to_markdown(). While a small set of Markdown metacharacters are escaped, characters such as < and > are preserved, so untrusted input that is safe in to_html() — including entity-decoded text (e.g. &lt;script&gt;) or text from RCDATA/RAWTEXT-parsed elements like <title>, <textarea>, <noscript>, and <plaintext> — can be emitted as raw HTML in the Markdown output, enabling a sanitizer bypass and potential cross-site scripting when that output is rendered.

## Remediation

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

## Package advisory (CVE-2026-8445)

Affected packages:

- `justhtml < 1.12.0`

Patched in:

- `justhtml 1.12.0`

Source: https://osv.dev/vulnerability/GHSA-3rcm-vjrc-p45j