What’s Vulnerable › Vulnerabilities

CVE-2026-58402: Hugo default code block renderer XSS via unescaped code-fence language

• Severity: medium (CVSS 5.4 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: 2026-07-06 · updated 2026-10-25
• Weakness: CWE-79

Description

Hugo is a static site generator. From 0.60.0 until 0.163.3, Hugo's default code-block renderer wrote the Markdown code-fence language or info-string into the code class="language-…" data-lang="…" wrapper without HTML escaping. A fence info-string containing a quote and a script payload breaks out of the attribute and injects a live script element. This issue is fixed in 0.163.3.

Affected products

• gohugoio hugo: from 0.60.0 before 0.163.3 — fixed in 0.163.3

How to fix

Upgrade to a fixed version: gohugoio hugo 0.163.3. Check the vendor advisory for mitigations.

References

• https://github.com/gohugoio/hugo/commit/ce1a7e0bce3713af40496ded3c2c0ceeed49231d
• https://github.com/gohugoio/hugo/pull/15051
• https://github.com/gohugoio/hugo/releases/tag/v0.163.3
• https://github.com/gohugoio/hugo/security/advisories/GHSA-q76j-gcg9-vxc6

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