UBUNTU-CVE-2026-59922
Mistune, a Python Markdown parser, has a denial of service vulnerability prior to version 3.3.0. The issue occurs when runs of closed tilde, equals-sign, or caret marker pairs around a character cause quadratic processing in the formatting plugin, leading to CPU exhaustion. This vulnerability is fixed in version 3.3.0.
AI Analysis
Technical Summary
Mistune versions before 3.3.0 contain a denial of service vulnerability due to inefficient processing in src/mistune/plugins/formatting.py. Specifically, when strikethrough, mark, or insert plugins scan for matching markers (closed tilde, equals-sign, or caret pairs) around characters, the algorithm performs quadratic work by checking from each possible start position. This can be exploited to cause CPU exhaustion, resulting in denial of service. The issue is resolved in Mistune version 3.3.0.
Potential Impact
An attacker can cause a denial of service by triggering excessive CPU usage in Mistune Markdown parsing, leading to service disruption or application unavailability. There is no impact on confidentiality or integrity.
Mitigation Recommendations
Upgrade Mistune to version 3.3.0 or later, where this vulnerability is fixed. No other mitigation or temporary workaround is indicated.
UBUNTU-CVE-2026-59922
Description
Mistune, a Python Markdown parser, has a denial of service vulnerability prior to version 3.3.0. The issue occurs when runs of closed tilde, equals-sign, or caret marker pairs around a character cause quadratic processing in the formatting plugin, leading to CPU exhaustion. This vulnerability is fixed in version 3.3.0.
CVSS v3.1
Score 7.5high
Affected software
pkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]+really0.8.4-1?arch=source&distro=jammypkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Mistune versions before 3.3.0 contain a denial of service vulnerability due to inefficient processing in src/mistune/plugins/formatting.py. Specifically, when strikethrough, mark, or insert plugins scan for matching markers (closed tilde, equals-sign, or caret pairs) around characters, the algorithm performs quadratic work by checking from each possible start position. This can be exploited to cause CPU exhaustion, resulting in denial of service. The issue is resolved in Mistune version 3.3.0.
Potential Impact
An attacker can cause a denial of service by triggering excessive CPU usage in Mistune Markdown parsing, leading to service disruption or application unavailability. There is no impact on confidentiality or integrity.
Mitigation Recommendations
Upgrade Mistune to version 3.3.0 or later, where this vulnerability is fixed. No other mitigation or temporary workaround is indicated.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-59922
- Osv Schema Version
- 1.7.0
- Aliases
- []
- Ecosystems
- ["Ubuntu:16.04:LTS","Ubuntu:18.04:LTS","Ubuntu:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:25.10","Ubuntu:26.04:LTS"]
- Database Specific Severity
- null
- Cvss Version
- 3.1
Threat ID: 6a58b45468715ace43d6b992
Added to database: 07/16/2026, 10:37:08 UTC
Last enriched: 07/16/2026, 11:31:07 UTC
Last updated: 07/31/2026, 19:24:47 UTC
Views: 4
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