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Fencer Vulns
medium 6.1

CVE-2026-5160 json

goldmark vulnerable to Cross-site Scripting (XSS)

published 2026-04-15 6 mo ago modified 2026-09-10 1 mo ago also GHSA-c97m-vxhj-p7j6 , GO-2026-5320 , EUVD-2026-22836

cvss
6.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/yuin/goldmark/renderer/html 1.7.17
  • go github.com/yuin/goldmark 1.7.17
  • n/a github.com/yuin/goldmark/renderer/html 1.7.17
  • golang-github-yuin-goldmark Debian 14 1.8.2-1

debian advisories DEBIAN-CVE-2026-5160

  • mcphost Linux Micro 6.2 0.34.0-160000.3.1

suse advisories SUSE-SU-2026:22994-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1
  • mcphost openSUSE Leap 16.0 0.34.0-160000.3.1
  • mcphost openSUSE Tumbleweed 0.34.0-9.1

opensuse advisories openSUSE-SU-2026:21483-1openSUSE-SU-2026:21480-1openSUSE-SU-2026:11366-1

  • gh Azure Linux 3.0 2.62.0-15
  • telegraf Azure Linux 3.0 1.31.0-19

azure linux advisories AZL-83048AZL-83060

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-5160 updated cvss 6.1

github.com/yuin/goldmark/renderer/html: github.com/yuin/goldmark/renderer/html: Cross-site Scripting due to improper URL validation

  • Red Hat Custom Metric Autoscaler operator for Red Hat Openshift custom-metrics-autoscaler/custom-metrics-autoscaler-rhel9, custom-metrics-autoscaler/custom-metrics-autoscaler-adapter-rhel9, custom-metrics-autoscaler/custom-metrics-autoscaler-rhel9-operator, custom-metrics-autoscaler/custom-metrics-autoscaler-admission-webhooks-rhel9
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 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
CNA 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CNA 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
GitHub 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
go github.com/yuin/goldmark/renderer/html
<1.7.17
1.7.17
go github.com/yuin/goldmark
<1.7.17
1.7.17

Affected products

  • n/a github.com/yuin/goldmark/renderer/html

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.