Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the Include directive in src/mistune/directives/include.py detects only direct self-includes and not indirect cycles, allowing two markdown files that include each other to trigger unbounded recursion, raise RecursionError, and crash the rendering request. This issue is fixed in version 3.3.0.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00352.

Exploitation none

Automatable yes

Technical Impact partial

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 affected
Version Status Constraints
< 3.3.0 affected —

No data.

No data.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-8mpj-m6qm-5qr8 Mistune directives/include: mutual `.. include::` recursion crashes the renderer with `RecursionError`, denial of service via two attacker-controlled markdown files
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/lepture/mistune/commit/1bef343ade163fc3bb95572b15be720084cdb993 cve-icon cve-icon
https://github.com/lepture/mistune/releases/tag/v3.3.0 cve-icon cve-icon
https://github.com/lepture/mistune/security/advisories/GHSA-8mpj-m6qm-5qr8 cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-59927 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-59927 cve-icon
History

Thu, 09 Jul 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-835
References
Metrics threat_severity

None

 threat_severity

Important

Wed, 08 Jul 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 08 Jul 2026 18:45:00 +0000

Type Values Removed Values Added
First Time appeared Lepture
Lepture mistune
Vendors & Products Lepture
Lepture mistune

Wed, 08 Jul 2026 17:00:00 +0000

Type Values Removed Values Added
Description Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the Include directive in src/mistune/directives/include.py detects only direct self-includes and not indirect cycles, allowing two markdown files that include each other to trigger unbounded recursion, raise RecursionError, and crash the rendering request. This issue is fixed in version 3.3.0.
Title Mistune directives/include: mutual `.. include::` recursion crashes the renderer with `RecursionError`, denial of service via two attacker-controlled markdown files
Weaknesses CWE-674
CWE-755
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-07-08T19:45:20.799Z

Reserved: 2026-07-07T18:20:06.126Z

Link: CVE-2026-59927

cve-icon Vulnrichment

Updated: 2026-07-08T19:45:11.248Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Important

Publid Date: 2026-07-08T16:24:37Z

Links: CVE-2026-59927 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-07-26T17:30:17Z

Weaknesses