Is CVE-2026-115354 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-115354 being exploited in the wild.

How severe is CVE-2026-115354?

Medium severity, with a CVSS score of 6.5, published 22 October 2026.

Is there a fix for CVE-2026-115354?

Yes: fixed in 3.3.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-115354 attacked?

It is attacked over the network.

Am I affected by CVE-2026-115354?

Check whether you run Lepture Mistune at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-115354: Mistune path traversal in Include directive

CVE-2026-115354 · Severity: medium · CVSS 6.5 · Published 2026-10-22

Mistune is a Markdown parser library used to convert Markdown documents into HTML. When the optional Include directive is enabled, attackers can craft malicious Markdown files to read arbitrary files from the server (such as /etc/passwd) and inject unescaped code into the rendered output. This could lead to data exposure or code injection attacks if applications process untrusted Markdown files.

Technologies: Lepture Mistune. Vendors: Lepture.

Quick answers

Is CVE-2026-115354 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-115354 being exploited in the wild.
How severe is CVE-2026-115354?: Medium severity, with a CVSS score of 6.5, published 22 October 2026.
Which products and versions are affected?: Lepture Mistune before 3.3.0.
Is there a fix for CVE-2026-115354?: Yes: fixed in 3.3.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-115354 attacked?: It is attacked over the network.
Am I affected by CVE-2026-115354?: Check whether you run Lepture Mistune at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: 3.3.0

Technical details

The vulnerability is a path traversal flaw in src/mistune/directives/include.py where the Include directive resolves file paths without validating against a root directory or allowlist. When Markdown.read(path) is called with attacker-controlled input, relative paths like "../secret.txt" or absolute paths allow reading files outside the intended directory. Non-Markdown included content is embedded in HTML without escaping, preserving HTML/script tags in the output.

Affected products

lepture Mistune before 3.3.0

Timeline

2026-06-21: disclosed
2026-10-22: advisory

References

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