XSS in Yuin Goldmark
CVE-2026-5160
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:alert(1) is not recognized as dangerous during validation, leading to arbitrary script execution in the context of applications that render the URL.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (25.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 25.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.001
Affected products
- Yuin Goldmark
- Github.com/yuin/goldmark/renderer/html — versions 0
Weakness classification (CWE)
References
- security.snyk.io/vuln/SNYK-GOLANG-GITHUBCOMYUINGOLDMARKRENDERERHTML-15838406 (Third Party Advisory, Mitigation)
- github.com/yuin/goldmark/commit/cb46bbc4eca29d55aa9721e04ad207c23ccc44f9 (Patch)
Frequently asked questions
- What is CVE-2026-5160?
- CVE-2026-5160 is a medium-severity vulnerability in Yuin Goldmark, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-04-15.
- How severe is CVE-2026-5160?
- Medium severity. CVSS v3 base score is 6.1 out of 10.