CVE-2026-59927: CWE-674: Uncontrolled Recursion in lepture mistune
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.
AI Analysis
Technical Summary
CVE-2026-59927 describes an uncontrolled recursion vulnerability in the Include directive of Mistune before version 3.3.0. The directive fails to detect indirect inclusion cycles between markdown files, which can lead to unbounded recursion, triggering a RecursionError and causing the rendering request to crash. This vulnerability is categorized under CWE-674 (Uncontrolled Recursion) and CWE-755 (Improper Handling of Exceptional Conditions). The issue has been addressed and fixed in Mistune version 3.3.0.
Potential Impact
An attacker can craft markdown files that include each other indirectly, causing the parser to enter unbounded recursion, which raises a RecursionError and crashes the rendering process. This results in a denial of service (DoS) condition affecting availability. There is no impact on confidentiality or integrity.
Mitigation Recommendations
Upgrade Mistune to version 3.3.0 or later, where the vulnerability is fixed. Patch status is confirmed by the vendor's advisory indicating the fix in 3.3.0. No other mitigation is specified or required.
CVE-2026-59927: CWE-674: Uncontrolled Recursion in lepture mistune
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.
CVSS v3.1
Score 5.3medium
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-59927 describes an uncontrolled recursion vulnerability in the Include directive of Mistune before version 3.3.0. The directive fails to detect indirect inclusion cycles between markdown files, which can lead to unbounded recursion, triggering a RecursionError and causing the rendering request to crash. This vulnerability is categorized under CWE-674 (Uncontrolled Recursion) and CWE-755 (Improper Handling of Exceptional Conditions). The issue has been addressed and fixed in Mistune version 3.3.0.
Potential Impact
An attacker can craft markdown files that include each other indirectly, causing the parser to enter unbounded recursion, which raises a RecursionError and crashes the rendering process. This results in a denial of service (DoS) condition affecting availability. There is no impact on confidentiality or integrity.
Mitigation Recommendations
Upgrade Mistune to version 3.3.0 or later, where the vulnerability is fixed. Patch status is confirmed by the vendor's advisory indicating the fix in 3.3.0. No other mitigation is specified or required.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-07-07T18:20:06.126Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a4e81d8c9d9e3dbe3746a55
Added to database: 07/08/2026, 16:59:04 UTC
Last enriched: 07/08/2026, 17:13:31 UTC
Last updated: 08/22/2026, 10:52:10 UTC
Views: 92
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