CVE-2026-59924 Mistune: Arbitrary File Read via Include directive path traversal

Medium 5.9 Published 8 Jul 2026 Updated 8 Jul 2026

Attackers can read arbitrary files outside the intended directory by crafting malicious include paths in Markdown files processed by Mistune.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-59924?

CVE-2026-59924 is a medium-severity path traversal vulnerability in lepture mistune, published on 8 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, Include.parse() joins and normalizes user-supplied include paths without verifying that the result remains within the intended markdown directory, allowing crafted include paths to access files outside that directory when markdown files are processed using md.read(). This issue is fixed in version 3.3.0.

Weakness: CWE-22

Which versions are affected by CVE-2026-59924?

3 open source packages ship an affected version, including mistune. It affects 1 product.

Package	Affected	Fixed in
`mistune` PyPI	All versions	`3.3.0`
`mistune` PyPI	All versions	`3.3.0`
`mistune` PyPI	All versions	`3.3.0`

Products include Mistune Project Mistune.

How do I fix CVE-2026-59924?

Upgrade mistune to 3.3.0 or later.

Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.

Is CVE-2026-59924 being exploited?

There is no known exploitation of CVE-2026-59924 in the wild and no public exploit code.

Sources

Also known as DEBIAN-CVE-2026-59924, ECHO-902c-bf12-91ee, GHSA-r4rv-85jg-w4mf, PYSEC-2026-2212, UBUNTU-CVE-2026-59924.