CVE-2026-76098: CWE-674: Uncontrolled Recursion in lepture mistune
Mistune, a Python Markdown parser, has a denial-of-service vulnerability in versions 3.3.0 through 3.3.2. The issue arises from uncontrolled recursion during HTML rendering of deeply nested emphasis tokens created by consecutive asterisks. This can cause Python's recursion limit to be exceeded, raising a RecursionError and crashing the parsing process. The vulnerability is fixed in version 3.3.3.
AI Analysis
Technical Summary
CVE-2026-76098 affects Mistune versions 3.3.0 to 3.3.2, where the HTMLRenderer.render_token() function recursively processes deeply nested emphasis tokens generated from consecutive asterisk characters in Markdown input. This uncontrolled recursion can exceed Python's recursion limit, causing a RecursionError and resulting in a denial-of-service condition by crashing the parser. The vulnerability is classified under CWE-674 (Uncontrolled Recursion). The issue is resolved in Mistune version 3.3.3.
Potential Impact
An attacker can craft Markdown content with deeply nested emphasis tokens that cause the parser to exceed the recursion limit, triggering a RecursionError and crashing the parsing process. This leads to a denial-of-service (DoS) condition, impacting availability of services relying on Mistune for Markdown parsing. There is no impact on confidentiality or integrity.
Mitigation Recommendations
Upgrade Mistune to version 3.3.3 or later, where this uncontrolled recursion vulnerability has been fixed. No other mitigation is indicated or required.
CVE-2026-76098: CWE-674: Uncontrolled Recursion in lepture mistune
Description
Mistune, a Python Markdown parser, has a denial-of-service vulnerability in versions 3.3.0 through 3.3.2. The issue arises from uncontrolled recursion during HTML rendering of deeply nested emphasis tokens created by consecutive asterisks. This can cause Python's recursion limit to be exceeded, raising a RecursionError and crashing the parsing process. The vulnerability is fixed in version 3.3.3.
CVSS v3.1
Score 7.5high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-76098 affects Mistune versions 3.3.0 to 3.3.2, where the HTMLRenderer.render_token() function recursively processes deeply nested emphasis tokens generated from consecutive asterisk characters in Markdown input. This uncontrolled recursion can exceed Python's recursion limit, causing a RecursionError and resulting in a denial-of-service condition by crashing the parser. The vulnerability is classified under CWE-674 (Uncontrolled Recursion). The issue is resolved in Mistune version 3.3.3.
Potential Impact
An attacker can craft Markdown content with deeply nested emphasis tokens that cause the parser to exceed the recursion limit, triggering a RecursionError and crashing the parsing process. This leads to a denial-of-service (DoS) condition, impacting availability of services relying on Mistune for Markdown parsing. There is no impact on confidentiality or integrity.
Mitigation Recommendations
Upgrade Mistune to version 3.3.3 or later, where this uncontrolled recursion vulnerability has been fixed. No other mitigation is indicated or required.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-08-18T21:17:32.201Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a8ca814acd9273b49150585
Added to database: 08/24/2026, 20:22:44 UTC
Last enriched: 08/24/2026, 20:37:05 UTC
Last updated: 08/24/2026, 21:26:37 UTC
Views: 5
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