Bug 2507882

Summary: CVE-2026-59922 python-mistune: Mistune: Denial of Service via crafted input [epel-all]
Product: [Fedora] Fedora EPEL Reporter: Hardik Vyas <hvyas>
Component: python-mistuneAssignee: Neil Hanlon <neil>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: epel10CC: epel-packagers-sig, mhroncok, neil, python-packagers-sig, romain.geissler
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["a41b138c-e0aa-4401-a565-b7b0a801745b"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 2498140    

Description Hardik Vyas 2026-07-28 06:53:11 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a run of closed tilde, equals-sign, or caret marker pairs around a character causes quadratic work in src/mistune/plugins/formatting.py when the strikethrough, mark, or insert plugin scans for matching markers from each possible start position, allowing denial of service through CPU exhaustion. This issue is fixed in version 3.3.0.