CVE-2026-115350 Details
Description
Mistune before 3.3.0 contains a cross-site scripting vulnerability in the Include directive that emits included .html, .xhtml, or .htm file content as raw block_html tokens. Attackers who can plant an HTML file readable by the renderer can reference it via an include directive, combined with path traversal, to execute stored scripts when escape=False is set.
A cross-site scripting (XSS) vulnerability has been identified in Mistune versions prior to 3.3.0. The issue arises in the Include directive, which processes .html, .xhtml, or .htm files as raw block_html tokens. This vulnerability allows attackers to execute stored scripts by planting an HTML file that the renderer can read. The exploitation requires combining the Include directive with path traversal, and setting escape=False, which is a common configuration for sites that trust their markdown content.
Users are advised to update to Mistune version 3.3.0 or later, where this vulnerability has been patched.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Oct 22, 2026CISA-ADP
Assessed Oct 29, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/lepture/mistune/security/advisories/GHSA-96vr-jm8v-g22j | [email protected] | AdvisoryExploitRemedyVendor |
| https://www.vulncheck.com/advisories/mistune-before-3.3.0-stored-xss-via-include-directive-html-files | [email protected] | Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-79 | Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Mistune | <= 3.2.1 (semver) |
CPE
Remediation
| |
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Oct 29, 2026 | CVE Modified | CISA-ADP |
| Oct 22, 2026 | New CVE Received | [email protected] |