CVE-2026-115355

High

Description

Mistune before 3.3.0 contains a path traversal vulnerability in the Include directive that allows attackers to read arbitrary files by supplying ../ sequences in include paths. Attackers can also inject HTML through unescaped error messages and included file contents to perform cross-site scripting even when escape=True is set.

SeverityHigh

CVSS7.5

Exploit probability—

ProductMistune

PublishedOct 22, 2026

First seenOct 22, 2026

Weakness typeCWE-22Path traversal

How to fix

Update

mistune3.3.0 or later

Vendor advisories

github.com/lepture/mistune/security/advisories/GHSA-h7ww-273w-6cm8

Affected products

Product	Affected versions	Fixed in
mistunePyPI	v < 3.3.0	3.3.0

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