VDB
CVE-2026-59928
CVE-2026-59928
PUBLISHED
CVSS 7.5 HIGH
Reported by GitHub_M · Published July 8, 2026
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a Markdown document containing many repeated or distinct reference-link definitions causes quadratic work in src/mistune/block_parser.py and the ref_links environment dictionary handling, allowing denial of service through CPU exhaustion. This issue is fixed in version 3.3.0.
Risk Scores
CVSS 3.1
7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| lepture | mistune | < 3.3.0 |
| lepture | mistune | < 3.3.0, < 3.3.0 |
| PyPI | mistune | 0 |
Timeline
- Jul 8, 2026 CVE Published
- Jul 9, 2026 EPSS Score
- Jul 9, 2026 Coalition ESS Score
- Aug 7, 2026 EPSS Score
- Aug 21, 2026 Security Advisory
References
- https://github.com/lepture/mistune/security/advisories/GHSA-ffq3-xpv3-j92q x_refsource_CONFIRM
- https://github.com/lepture/mistune/commit/2b04d7ba341c16ac78fe82d3076bdd5c3de87c69 x_refsource_MISC
- https://github.com/lepture/mistune/releases/tag/v3.3.0 x_refsource_MISC
- https://nvd.nist.gov/vuln/detail/CVE-2026-59928 advisory
- https://github.com/advisories/GHSA-ffq3-xpv3-j92q advisory
- https://github.com/pypa/advisory-database/tree/main/vulns/mistune/PYSEC-2026-2216.yaml advisory