Bug 2458616 (CVE-2026-5160)

Summary: CVE-2026-5160 github.com/yuin/goldmark/renderer/html: github.com/yuin/goldmark/renderer/html: Cross-site Scripting due to improper URL validation
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: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in github.com/yuin/goldmark/renderer/html. This Cross-site Scripting (XSS) vulnerability allows a remote attacker to execute arbitrary scripts in the context of applications that render a malicious URL. The flaw stems from an improper ordering of URL validation and normalization, where the component validates link destinations before resolving HTML entities. This enables an attacker to bypass protocol filtering by encoding dangerous schemes using HTML5 named character references, leading to unauthorized code execution.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2458968, 2458969, 2458970, 2458972, 2458973, 2458974, 2458975, 2458978, 2458979, 2458980, 2458981, 2458982, 2458983, 2458985, 2458987, 2458988, 2458989, 2458992, 2458993, 2458995, 2458996, 2458971, 2458976, 2458984, 2458986, 2458991, 2458994, 2458997, 2458998    
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Description OSIDB Bzimport 2026-04-15 06:01:14 UTC 
Versions of the package github.com/yuin/goldmark/renderer/html before 1.7.17 are vulnerable to Cross-site Scripting (XSS) due to improper ordering of URL validation and normalization. The renderer validates link destinations using a prefix-based check (IsDangerousURL) before resolving HTML entities. This allows an attacker to bypass protocol filtering by encoding dangerous schemes using HTML5 named character references. For example, a payload such as javascript&colon;alert(1) is not recognized as dangerous during validation, leading to arbitrary script execution in the context of applications that render the URL.
Comment 2 Marco Benatto 2026-04-16 18:20:54 UTC 
Public upstream commit fixing this issue:
https://github.com/yuin/goldmark/commit/cb46bbc4eca29d55aa9721e04ad207c23ccc44f9