Mistune has Denial of Service — RecursionError via Excessive Emphasis Markers in Markdown
CVE-2026-76098 is fixed in 3 products on 1 platform, first by ALAS2023-2026-2148, released September 14, 2026. It is not reported as exploited. Patch Radar priority: High.
Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities: CVE-2026-76098: Mistune is a Python Markdown parser with renderers and plugins. Versions 3.3.0 through 3.3.2 are vulnerable to DoS through deeply nested tokens. HTML rendering creates deeply nested emphasis tokens from consecutive asterisk characters, and recursive rendering in HTMLRenderer.render_token() can exceed Python's recursion limit and raise RecursionError, allowing crafted Markdown to crash a parsing process. This issue is fixed in version 3.3.3
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| python-mistune-debugsource · amzn 2023 | 0.8.3-14.amzn2023.0.4 | ALAS2023-2026-2148 | Sep 14, 2026 |
| python3-mistune · amzn 2023 | 0.8.3-14.amzn2023.0.4 | ALAS2023-2026-2148 | Sep 14, 2026 |
| python3-mistune-debuginfo · amzn 2023 | 0.8.3-14.amzn2023.0.4 | ALAS2023-2026-2148 | Sep 14, 2026 |
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