Mistune vulnerable to catastrophic backtracking
In Mistune through 2.0.2, support of inline markup is implemented by using regular expressions that can involve a high amount of backtracking on certain edge cases. This behavior is commonly named catastrophic backtracking.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | mistune | >= 2.0.0a1, < 2.0.3 | 2.0.3 |
References
- https://github.com/lepture/mistune/commit/a6d43215132fe4f3d93f8d7e90ba83b16a0838b2
- https://github.com/lepture/mistune/releases
- https://github.com/advisories/GHSA-fw3v-x4f2-v673
- https://nvd.nist.gov/vuln/detail/CVE-2022-34749
- https://github.com/lepture/mistune/issues/314#issuecomment-1223972386
- https://github.com/lepture/mistune/commit/ca1e7b506850f4e488823fc7338b49a8f9852718
- https://github.com/lepture/mistune
- https://github.com/pypa/advisory-database/tree/main/vulns/mistune/PYSEC-2022-237.yaml
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TQHXITQ2DSBYOILKHXBSBB7PFBPZHF63
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H- Weakness (CWE)
CWE-1333- Platform
- Python (PyPI)
- Package
mistune- Disclosed
- 25.07.2022
- Updated
- 11.10.2026 11:20
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2022-237 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-fw3v-x4f2-v673 - CC BY 4.0
Vulnerability history: mistune
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 20
- First → latest
- 10.2017 09.2026
- Without a fix
- 1
- Exploited in attacks
- 0
Severity breakdown
- High 7
- Medium 13
Disclosures per year
- 2017: 2
- 2018: 0
- 2019: 0
- 2020: 0
- 2021: 0
- 2022: 1
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 17
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Mistune vulnerable to catastrophic backtracking this entry
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