Threats Tagged 'cve-2026-59930'

In `src/mistune/directives/image.py`, the `render_figure()` function concatenates `figclass` and `figwidth` options directly into HTML attributes without escaping (lines 152-168). This allows attribute injection and XSS even when `HTMLRenderer(escape=True)` is used, because these values bypass the inline renderer. Other attributes in the same file (src, alt, style) are properly escaped; figclass/figwidth were missed.

The adr-viewer software's Mistune toc plugin and TableOfContents directive generate heading IDs using a predictable numeric scheme (toc_1, toc_2, etc.) without incorporating the heading text. This allows an attacker who can inject HTML with matching IDs to cause collisions, leading to navigation hijacking, CSS/JS selector misapplication, and broken accessibility associations. The issue arises because HTML requires unique IDs, but Mistune's default behavior ignores this, enabling attacker-controlled elements to shadow legitimate headings. The vulnerability is rated medium severity with a CVSS score of 4.3 and has a patch available.

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the toc plugin and TableOfContents directive generate heading IDs as predictable toc_N values without slugifying the heading text, allowing attacker-controlled id="toc_N" content to collide with generated anchors and redirect same-page navigation, CSS selectors, or JavaScript handlers. This issue is fixed in version 3.3.0.