---
id: "CVE-2026-115353"
kind: "vulnerability"
aliases: ["CVE-2026-115353"]
title: "Mistune: RST include directive reads arbitrary files via path traversal"
severity: "critical"
cvss: 9.2
epss: 0.00387
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["mistune", "package", "python", "web-apps"]
not_affected_if: ["no-untrusted-rst-input", "version-3.3.0-or-later"]
published_at: "2026-10-22T19:17:41+00:00"
first_seen_at: "2026-10-23T21:57:31+00:00"
updated_at: "2026-10-24T07:15:51+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-115353", "first_seen_at": "2026-10-23T21:57:31+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-115353", "first_seen_at": "2026-10-24T07:15:51+00:00"}]
---

# Mistune: RST include directive reads arbitrary files via path traversal

Mistune before 3.3.0 lets an attacker supply relative or absolute paths in an RST include directive. The rendered HTML then embeds sensitive local files such as credentials or environment data.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

Check the installed mistune version with pip show mistune or pip freeze; anything below 3.3.0 is exposed. Search your code for mistune usage that renders untrusted RST input with include directives enabled.

## Fix

Upgrade mistune to 3.3.0 or later.

## Timeline

- 2026-10-23T21:57:31+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-115353
- 2026-10-24T07:15:51+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-115353

## From the sources

Mistune before 3.3.0 contains a path traversal vulnerability in the RST include directive that allows attackers to read arbitrary files by supplying relative or absolute paths. Attackers can submit markdown containing include directives referencing ../ sequences or absolute paths to embed sensitive files like credentials or environment data in rendered HTML.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_