---
id: CVE-2026-115350
title: Mistune before 3.3.0 Stored XSS via Include Directive HTML Files
summary: >-
  Mistune before 3.3.0 contains a cross-site scripting vulnerability in the
  Include directive that emits included .html, .xhtml, or .htm file content as
  raw block_html tokens. Attackers who can plant an HTML file readable by the
  renderer c…
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'
cvssSource: cna
cwe:
  - CWE-79
vendor: lepture
product: mistune
affected:
  - mistune < 3.3.0
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-29T02:24:48.848275Z'
published: '2026-10-22'
updated: '2026-10-29'
sourceUpdated: '2026-10-29T02:24:58.381Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-115350'
references:
  - url: 'https://github.com/lepture/mistune/security/advisories/GHSA-96vr-jm8v-g22j'
    label: GitHub Security Advisory (GHSA-96vr-jm8v-g22j)
  - url: >-
      https://www.vulncheck.com/advisories/mistune-before-3.3.0-stored-xss-via-include-directive-html-files
    label: >-
      VulnCheck Advisory: Mistune before 3.3.0 Stored XSS via Include Directive
      HTML Files
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-115350.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-115350'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2559350'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-115350'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-115350'
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00188
epssPercentile: 0.08493
ingestedAt: '2026-10-22T22:00:50.395Z'
---

## Overview

Mistune before 3.3.0 contains a cross-site scripting vulnerability in the Include directive that emits included .html, .xhtml, or .htm file content as raw block_html tokens. Attackers who can plant an HTML file readable by the renderer can reference it via an include directive, combined with path traversal, to execute stored scripts when escape=False is set.

## Affected

- `mistune < 3.3.0`

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat OpenShift AI (RHOAI), Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat OpenShift AI (RHOAI), Red Hat OpenShift Container Platform 4 · updated 2026-10-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-115350.json)