---
id: CVE-2026-105829
title: >-
  League CommonMark from 1.3.0 before 2.10.2 contains a cross-site scripting
  vulnerability that allows users posting Markdown to bypass the
  DisallowedRawHtml extension by ending raw HTML with a bare disallowed tag name
summary: >-
  League CommonMark from 1.3.0 before 2.10.2 contains a cross-site scripting
  vulnerability that allows users posting Markdown to bypass the
  DisallowedRawHtml extension by ending raw HTML with a bare disallowed tag
  name. Attackers can place…
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'
cwe:
  - CWE-80
vendor: thephpleague
product: commonmark
affected:
  - commonmark
published: '2026-10-08'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T21:33:42.423'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-105829'
references:
  - url: >-
      https://github.com/thephpleague/commonmark/security/advisories/GHSA-97jj-33gv-5xf9
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/league-commonmark-1.3.0-before-2.10.2-stored-xss-via-disallowedrawhtml-bypass
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-08T14:47:16.360Z'
---

## Overview

League CommonMark from 1.3.0 before 2.10.2 contains a cross-site scripting vulnerability that allows users posting Markdown to bypass the DisallowedRawHtml extension by ending raw HTML with a bare disallowed tag name. Attackers can place a lone <script or <iframe line followed by a block supplying attributes like src or onload, executing stored scripts in viewers' browsers under default GFM settings.

## Remediation

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