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OpenAdvisories
Medium · 6.1 CVE-2026-44708 EUVD-2026-31993GHSA-8g87-j6q8-g93xPYSEC-2026-2206

Mistune Math Plugin XSS Escape Bypass

Published May 26, 2026 · Updated May 27, 2026 · Assigned by GitHub_M

Description

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, the mistune math plugin renders inline math ($...$) and block math ($$...$$) by concatenating the raw user-supplied content directly into the HTML output without any HTML escaping. This occurs even when the parser is explicitly created with escape=True, which is supposed to guarantee that all user-controlled text is sanitised before reaching the DOM. This vulnerability is fixed in 3.2.1.

Affected products

VendorProductAffectedFixed
lepture mistune < 3.2.1 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 mistune No fix yet —
Debian 13 mistune No fix yet —
Debian 12 mistune No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 mistune +1 No fix yet —
Ubuntu 26.04 LTS mistune No fix yet —
Ubuntu 25.10 mistune +1 No fix yet —
Ubuntu 24.04 LTS mistune No fix yet —
Ubuntu 20.04 LTS mistune No fix yet —
Show 2 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 18.04 LTS mistune No fix yet —
Ubuntu 16.04 LTS mistune No fix yet —

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 python-mistune 3.2.1-1 —

Wolfi

ReleasePackageFixed inAdvisory
Wolfi rolling kubeflow-pipelines-visualization-server 2.16.1-r2 —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI mistune <= 3.2.0 — GHSA-8g87-j6q8-g93x
PyPI mistune < 3.2.1 3.2.1 PYSEC-2026-2206

References