CVE-2026-59925
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, long sequences of well-formed double-asterisk or triple-asterisk emphasis pairs around a character cause quadratic work in src/mistune/inline_parser.py because the parser scans forward for matching close markers from every potential opening run, allowing denial of service in default Mistune parsing. This issue is fixed in version 3.3.0.
- CVSS 3.1
- 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS
- 0.6% chance of exploitation in the next 30 days; higher than 50% of CVEs (scores of 2026-10-25)
- CWEs
- CWE-407, CWE-1333
- Published
- Modified
- Record from
- the NVD, synced
Affected
- mistune_project:mistune
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-4j32-57v6-6g45 | PyPI | mistune | <3.3.0 | 3.3.0 |
| PYSEC-2026-2213 | PyPI | mistune | <3.3.0 | 3.3.0 |