CVE-2026-59928
Published:July 08, 2026
Updated:August 05, 2026
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a Markdown document containing many repeated or distinct reference-link definitions causes quadratic work in src/mistune/block_parser.py and the ref_links environment dictionary handling, allowing denial of service through CPU exhaustion. This issue is fixed in version 3.3.0.
Affected Packages
mistune (CONDA):
Affected version(s) >=0.5 <3.3.0Fix Suggestion:
Update to version 3.3.0https://github.com/lepture/mistune.git (GITHUB):
Affected version(s) >=v0.1.0 <v3.3.0Fix Suggestion:
Update to version v3.3.0mistune (PYTHON):
Affected version(s) >=0.1.0 <3.3.0Fix Suggestion:
Update to version 3.3.0mistune (PYTHON):
Affected version(s) >=0.1.0 <3.3.0Fix Suggestion:
Update to version 3.3.0Related Resources (7)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
EPSS
Base Score:
0.41