CVE-2026-44896 Details
Description
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.
A cross-site scripting (XSS) vulnerability has been identified in the Mistune Markdown parser, specifically in versions through 3.2.0. The issue arises in the 'render_figure()' function within the 'src/mistune/directives/image.py' file, where the 'figclass' and 'figwidth' options are concatenated directly into HTML attributes without proper escaping. This flaw enables attribute injection and XSS, even when 'HTMLRenderer(escape=True)' is applied, as these unescaped values circumvent the inline renderer. In contrast, other attributes such as 'src', 'alt', and 'style' are correctly escaped, leaving 'figclass' and 'figwidth' vulnerable.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 27, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-79 | Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| mistune project mistune | <= 3.2.0 |
CPE
Remediation
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Change History
7 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 24, 2026 | CVE Translated | [email protected] |
| Jul 23, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 9, 2026 | CVE Modified | [email protected] |
| May 28, 2026 | Initial Analysis | [email protected] |
| May 26, 2026 | New CVE Received | [email protected] |