Mistune has Denial of Service — RecursionError via Excessive Emphasis Markers in Markdown (lepture mistune)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.49 % · percentile 42 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Deferred
Description
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
Weaknesses (CWE)
- CWE-674 — Uncontrolled Recursion
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | GitHub_M |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · security-advisories@github.com (Secondary) |
Advisories
- GHSA-6m44-fpc8-c3rq — Mistune: Denial of Service — RecursionError via Excessive Emphasis Markers in Markdown
- PYSEC-2026-3863 — Mistune: Denial of Service — RecursionError via Excessive Emphasis Markers in Markdown
European references
- ENISA EUVD · EUVD-2026-65137
- GCVE · GCVE-0-2026-76098
Affected products
| Product | Versions |
|---|---|
| lepture · mistune | affected >= 3.3.0, < 3.3.3 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |