CVE-2026-44896 MEDIUM

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

Vendor Lepture

Product mistune

Weakness CWE-79 · XSS

Published May 26, 2026

Last update June 8, 2026

View on NVD All CVEs

CVSS base score

5.3/10

Attack vector Network

Attack complexity Low

Privileges required None

User interaction —

Confidentiality —

Integrity —

CVSS vector

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

What the vulnerability does

01Description

Mistune is a Python Markdown parser with renderers and plugins. In 3.2.0 and earlier, 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. Version 3.2.1 contains a patch.

Key dates

02Disclosure timeline

May 26, 2026 CVE published

June 8, 2026 Record updated

External resources

03References

NVD — National Vulnerability Database https://nvd.nist.gov/vuln/detail/CVE-2026-44896 CWE — Common Weakness Enumeration https://cwe.mitre.org/data/definitions/79.html

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04Related CVE

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