Bug 2460245 (CVE-2026-40890)

Summary: CVE-2026-40890 github.com/gomarkdown/markdown: github.com/gomarkdown/markdown: Denial of Service via malformed Markdown input
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: alcohan, gparvin, jbalunas, pahickey, rhaigner
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in github.com/gomarkdown/markdown, a Go library for parsing Markdown text and rendering as HTML. A remote attacker could exploit this vulnerability by providing a specially crafted malformed input. Specifically, input containing a '<' character not followed by a '>' character, when processed by the SmartypantsRenderer, can lead to an out-of-bounds read or a panic. This can result in a denial of service (DoS) for the application, making it unavailable to legitimate users.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2461583, 2461584, 2461585    
Bug Blocks:    

Description OSIDB Bzimport 2026-04-21 20:03:19 UTC 
The package `github.com/gomarkdown/markdown` is a Go library for parsing Markdown text and rendering as HTML. Processing a malformed input containing a < character that is not followed by a > character anywhere in the remaining text with a SmartypantsRenderer will lead to Out of Bounds read or a panic. This vulnerability is fixed with commit 759bbc3e32073c3bc4e25969c132fc520eda2778.