CVE-2026-5160: Cross-site Scripting (XSS) in github.com/yuin/goldmark

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-15 · updated 2026-06-17
Weakness: CWE-79

Description

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.

Affected products

github.com/yuin/goldmark/renderer/html: before 1.7.17 — fixed in 1.7.17
Go Github.Com/Yuin/Goldmark: before 1.7.17 — fixed in 1.7.17

How to fix

Upgrade to a fixed version: github.com/yuin/goldmark/renderer/html 1.7.17; Go Github.Com/Yuin/Goldmark 1.7.17. Check the vendor advisory for mitigations.

References

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