Mistune: XSS via unescaped figclass/figwidth in Figure directive_CVE-2026-44896

5.3 / 10

MEDIUM

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Description

Mistune is a Python Markdown parser with renderers and plugins. In 3.2.0 and realier, in src/mistune/directives/image.py, the render_figure() function concatenates figclass and figwidth options directly into HTML attributes without escaping. This allows attribute injection and XSS even when HTMLRenderer(escape=True) is used, because these values bypass the inline renderer.

Basic Information

ID CVE-2026-44896

Source GitHub_M

Published May 26, 2026 at 20:33

Affected Product

Vendor lepture

Product mistune

Version <= 3.2.0

Affected Versions lepture mistune <= 3.2.0

CWE Classification

CWE-79

References

github.com /lepture/mistune/security/advisories/GHSA-58cw-g322-p94v

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    "published": "2026-05-26T20:33:38.696Z",
    "modified": "2026-05-26T20:33:38.696Z",
    "type": "cve",
    "title": "Mistune: XSS via unescaped figclass/figwidth in Figure directive",
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