# CVE-2026-115353: Mistune before 3.3.0 Path Traversal via include Directive


- **Severity:** Critical 9.2 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 22 Oct 2026
- **Updated:** 22 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-115353, GHSA-9jjx-3hq3-hx4j, GHSA-pfvv-4pq6-mx74, UBUNTU-CVE-2026-115353

## What is CVE-2026-115353?

CVE-2026-115353 is a critical vulnerability in lepture mistune, published on 22 Oct 2026. 

### Official description

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.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-115353?


## How do I fix CVE-2026-115353?

No fix has been published for CVE-2026-115353 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-115353 being exploited?

There is no known exploitation of CVE-2026-115353 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-115353 and fix it if it is affected.

What it is: CVE-2026-115353 is a critical vulnerability in lepture mistune, published on 22 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-115353 in the wild and no public exploit code.

Affected product: lepture mistune. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-115353/ (Markdown: https://insights.sbomify.com/CVE-2026-115353/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-115353
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-115353
- OSV: https://osv.dev/vulnerability/CVE-2026-115353

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-115353/
Summaries are generated and may contain mistakes; the official description above is the record.