goldmark vulnerable to Cross-site Scripting (XSS)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.1 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N · score source

EPSS

• CVE-2026-5160: 0.29% estimated exploitation activity in the next 30 days; percentile 21.26 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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.

Published by the source

17 Apr 2026, 15:31 UTC

Last modified by the source

18 Apr 2026, 01:02 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-c97m-vxhj-p7j6

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# Patch Next advisory brief: CVE-2026-5160

Advisory: goldmark vulnerable to Cross-site Scripting (XSS)
IDs: CVE-2026-5160, GHSA-c97m-vxhj-p7j6
Record: https://patchnext.com/advisories/cve-2026-5160 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/yuin/goldmark/renderer/html 1.7.17. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/yuin/goldmark/renderer/html: affected < 1.7.17; fixed in 1.7.17

## Suggested inspection (read-only)
- Go github.com/yuin/goldmark/renderer/html: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/yuin/goldmark/renderer/html.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-c97m-vxhj-p7j6 (GitHub-reviewed advisory GHSA-c97m-vxhj-p7j6 lists affected ranges: Go github.com/yuin/goldmark/renderer/html >=0 <1.7.17)

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