Bug 2560125

Summary:	CVE-2026-115349 python-mistune: mistune: Denial of Service via deeply nested square brackets [epel-8]
Product:	[Fedora] Fedora EPEL	Reporter:	Ronit Dey <rdey>
Component:	python-mistune	Assignee:	Neil Hanlon <neil>
Status:	NEW ---	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	high
Version:	epel8	CC:	epel-packagers-sig, mhroncok, neil, python-packagers-sig, romain.geissler
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["60da071e-058c-4be0-88e2-6c567f2fef3e"]}
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Doc Text:		Story Points:	---
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Documentation:	---	CRM:
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2559278

Description Ronit Dey 2026-10-23 17:47:08 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 from 3.0.0 before 3.3.0 contains an algorithmic complexity denial of service vulnerability in the parse_link_text function in src/mistune/helpers.py. Attackers can submit markdown with deeply nested square brackets triggering quadratic parsing time, exhausting server CPU with small crafted requests.