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Vulnerability · Published Jul 6, 2026 · Assigned by GitHub_M

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

Medium 5.1

In plain English

A medium-severity cross-site scripting in hugo from gohugoio. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)5.1Medium
Exploit odds (30 days)0.3%top 77.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12hugono fix listedDEBIAN-CVE-2026-58402
Debian:13hugono fix listedDEBIAN-CVE-2026-58402
Debian:14hugo0.165.0-1DEBIAN-CVE-2026-58402
Gogithub.com/gohugoio/hugo0.163.3GHSA-q76j-gcg9-vxc6
Gogithub.com/gohugoio/hugo0.163.3GO-2026-5569
Ubuntu:22.04:LTShugono fix listedUBUNTU-CVE-2026-58402
Ubuntu:25.10hugono fix listedUBUNTU-CVE-2026-58402
Ubuntu:26.04:LTShugono fix listedUBUNTU-CVE-2026-58402
Ubuntu:26.10hugono fix listedUBUNTU-CVE-2026-58402

Affected products (as reported)

VendorProductVersions
gohugoio hugo >= 0.60.0, < 0.163.3

Weakness: CWE-79 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

References