Threats Tagged 'cve-2026-59922'

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.

Adr viewer's mistune markdown rendering with the strikethrough, mark, or insert plugins suffers from an algorithmic-complexity denial of service vulnerability (CVE-2026-59922). The formatting parser performs quadratic-time work when processing long runs of repeated markers like `~~x~~`, `==x==`, or `^^x^^`. This causes CPU usage to spike significantly with relatively small crafted inputs. The flaw arises because the parser scans forward from every potential start marker without memoization, resulting in O(N²) complexity. This vulnerability can be triggered by untrusted user input in applications using mistune with these plugins enabled. A patch is available to fix this inefficiency.

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a run of closed tilde, equals-sign, or caret marker pairs around a character causes quadratic work in src/mistune/plugins/formatting.py when the strikethrough, mark, or insert plugin scans for matching markers from each possible start position, allowing denial of service through CPU exhaustion. This issue is fixed in version 3.3.0.