Mistune: Arbitrary File Read via Include directive path traversal
Summary
A path traversal issue exists in mistune's Include directive when markdown files are processed using md.read(). A crafted include path can cause files outside the intended markdown directory to be accessed.
Details
The issue occurs in the Include.parse() method where user-supplied paths are joined and normalized without verifying that the resulting path remains within an expected directory.
relpath = self.parse_title(m)
dest = os.path.join(os.path.dirname(source_file), relpath)
dest = os.path.normpath(dest)Because the final path is not restricted to a trusted base directory, path traversal sequences such as ../ may reference files outside the intended location.
Proof of Concept
Create a markdown file:
.. include:: ../../../example.txtProcess it using:
import mistune
from mistune.directives import RSTDirective, Include
md = mistune.create_markdown(
plugins=[RSTDirective([Include()])]
)
result, state = md.read("test.md")
print(result)Impact
Applications that process untrusted markdown files with the Include directive enabled may allow unintended file access. The impact depends on how the feature is used and what files are accessible to the running process.
Recommended Fix
Validate the resolved path and ensure it remains within an allowed directory before opening the file.
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | mistune | < 3.3.0 | 3.3.0 |
Referencias
- https://github.com/lepture/mistune/releases/tag/v3.3.0
- https://github.com/lepture/mistune/commit/1bef343ade163fc3bb95572b15be720084cdb993
- https://github.com/lepture/mistune/security/advisories/GHSA-r4rv-85jg-w4mf
- https://nvd.nist.gov/vuln/detail/CVE-2026-59924
- https://github.com/lepture/mistune
- https://github.com/pypa/advisory-database/tree/main/vulns/mistune/PYSEC-2026-2212.yaml
- Vector CVSS
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N- Debilidad (CWE)
CWE-22- Plataforma
- Python (PyPI)
- Paquete
mistune- Publicada
- 08.07.2026
- Actualizado
- 11.10.2026 14:18
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2026-2212 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-r4rv-85jg-w4mf - CC BY 4.0
Historial de vulnerabilidades: mistune
Todas las vulnerabilidades publicadas de este paquete (Python (PyPI)), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 20
- Primera → última
- 10.2017 09.2026
- Sin corrección
- 1
- Explotada en ataques
- 0
Distribución por gravedad
- Alta 7
- Media 13
Divulgaciones por año
- 2017: 2
- 2018: 0
- 2019: 0
- 2020: 0
- 2021: 0
- 2022: 1
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 17
-
Mistune: Arbitrary File Read via Include directive path traversal esta entrada
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