Bug 2567342 - CVE-2026-121438 python-mistune08: mistune: Denial of Service via deeply nested Markdown brackets [epel-all]
Summary: CVE-2026-121438 python-mistune08: mistune: Denial of Service via deeply neste...
Keywords:
Status: NEW
Alias: None
Product: Fedora EPEL
Classification: Fedora
Component: python-mistune08
Version: epel10
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: ---
Assignee: Orphan Owner
QA Contact:
URL:
Whiteboard: {"flaws": ["ccfe68c3-afbd-4ba0-b035-d...
Depends On:
Blocks: CVE-2026-121438
TreeView+ depends on / blocked
 
Reported: 2026-11-05 15:24 UTC by Oleg Sushchenko
Modified: 2026-11-05 15:24 UTC (History)
4 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Type: ---
Embargoed:


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Description Oleg Sushchenko 2026-11-05 15:24:52 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 before 3.3.3 contains a denial of service vulnerability in InlineParser.parse_link that allows attackers to cause quadratic CPU growth by supplying balanced nested brackets. Attackers can submit crafted Markdown with thousands of nested bracket pairs not forming a valid link, triggering repeated _contains_nested_link scans that exhaust CPU in parsing applications.


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