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

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...

GHSA-Q76J-GCG9-VXC6 Hugo: XSS via unescaped code-fence language in default code block renderer

Hugo's default code-block renderer wrote the Markdown code-fence language / info-string into the wrapper without HTML escaping. A fence info-string containing a quote and a payload breaks out of the attribute and injects a live script element. This is not an issue if you fully trust every file...