CVE-2026-115355

Summary

Mistune: Path Traversal and XSS in Include directive

Severity

high

EPSS

0.5% (p40)

CWE

CWE-22

Also known as

GHSA-h7ww-273w-6cm8

Published

2026-10-23

Updated

2026-10-23

Advisory details

The Include directive in src/mistune/directives/include.py does not validate that the resolved file path stays within the source directory, allowing path traversal via ../ sequences to read arbitrary files.

Additionally, error messages and included file contents are rendered without HTML escaping, leading to XSS even when escape=True.

Affected functions:

• Path resolution (lines 27-31)
• block_error() in html.py (line 140)
• render_html_include() (line 72)

The Include plugin must be explicitly enabled via the plugins parameter.

References

• https://github.com/advisories/GHSA-h7ww-273w-6cm8
• https://github.com/lepture/mistune/security/advisories/GHSA-h7ww-273w-6cm8
• https://nvd.nist.gov/vuln/detail/CVE-2026-115355
• https://github.com/lepture/mistune/commit/1bef343ade163fc3bb95572b15be720084cdb993
• https://github.com/lepture/mistune/releases/tag/v3.3.0
• https://www.vulncheck.com/advisories/mistune-before-3.3.0-path-traversal-and-xss-via-include-directive

Related advisories

• GHSA-8cqv-vvq2-6p8c — high · PyPI/mistune
• CVE-2026-76098 — high · PyPI/mistune
• CVE-2026-114125 — critical · npm/storybook
• CVE-2026-61445 — critical · PyPI/praisonai
• CVE-2026-101894 — critical · npm/@xhmikosr/decompress
• CVE-2026-45140 — critical · Packagist/chamilo/chamilo-lms
• CVE-2026-61560 — critical · npm/@zereight/mcp-gitlab
• CVE-2026-75604 — critical · npm/next

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