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.
https://github.com/gohugoio/hugo/security/advisories/GHSA-q76j-gcg9-vxc6
https://github.com/gohugoio/hugo/releases/tag/v0.163.3
https://github.com/gohugoio/hugo/pull/15051
https://github.com/gohugoio/hugo/commit/ce1a7e0bce3713af40496ded3c2c0ceeed49231d
Published: 2026-07-06
Updated: 2026-07-06
Base Score: 7.5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P
Severity: High
Base Score: 10
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
Severity: Critical
Base Score: 5.1
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
Severity: Medium