medium6.1
CVE-2026-59926
Mistune is a Python Markdown parser with renderers and plugins.
Impact
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, render_admonition() in src/mistune/directives/admonition.py concatenates the Admonition directive :class: option into the HTML class attribute without escaping, allowing attribute injection and cross-site scripting even when HTMLRenderer escape mode is enabled. This issue is fixed in version 3.2.1.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | mistune | < 3.3.0 | 3.3.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Mistune Project | Mistune | before 3.3.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-g97x-gvcm-x72h
- https://github.com/lepture/mistune/security/advisories/GHSA-g97x-gvcm-x72h
- https://nvd.nist.gov/vuln/detail/CVE-2026-59926
- https://github.com/lepture/mistune/commit/a3cb6e5655308797e8be021d6c7b5bab13cbace2
- https://github.com/lepture/mistune/releases/tag/v3.2.1
- https://github.com/pypa/advisory-database/tree/main/vulns/mistune/PYSEC-2026-2214.yaml