Mistune: XSS via unescaped figclass/figwidth in Figure directive
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.3epss 0.2%
exploitation probability
0.2%top 90% of all CVEs
observed exploitation
nono source reports it
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.
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
Affected products
lepture · mistune