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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00387.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
lepture mistune unaffected
Version Status Constraints
0 affected < 3.3.0
3.3.0 unaffected —

No data.

No data.

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Vendors Products
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Project Subscriptions

Vendors Products
Mistune Project Subscribe
Mistune Subscribe
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-h7ww-273w-6cm8 Mistune: Path Traversal and XSS in Include directive
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/lepture/mistune/security/advisories/GHSA-h7ww-273w-6cm8 cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-115355 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-115355 cve-icon
https://www.vulncheck.com/advisories/mistune-before-3.3.0-path-traversal-and-xss-via-include-directive cve-icon cve-icon cve-icon
History

Fri, 23 Oct 2026 12:30:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 threat_severity

Important

Fri, 23 Oct 2026 00:45:00 +0000

Type Values Removed Values Added
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.
Title Mistune before 3.3.0 Path Traversal and XSS via Include Directive
First Time appeared Mistune Project
Mistune Project mistune
Weaknesses CWE-22
CPEs cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*
Vendors & Products Mistune Project
Mistune Project mistune
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-22T19:13:31.904Z

Reserved: 2026-10-22T11:20:02.627Z

Link: CVE-2026-115355

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-22T19:17:41.520

Modified: 2026-10-22T19:17:41.633

Link: CVE-2026-115355

cve-icon Redhat

Severity : Important

Publid Date: 2026-10-22T19:13:31Z

Links: CVE-2026-115355 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-23T07:15:17Z

Weaknesses