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.
Hugo is a static site generator. Prior to 0.162.0, Hugo accepts content files in several markup formats. Files mapped to the text/html media type (typically .html files under /content, or pages produced by a content adapter that sets content.mediaType = "text/html") had their body emitted verbatim into the rendered page. A site that ingests HTML content from an untrusted source could therefore be served stored cross-site scripting. This vulnerability is fixed in 0.162.0.
Hugo is a static site generator. From 0.43 to before 0.161.0, when building a Hugo site that uses Node-based asset pipelines (PostCSS, Babel, TailwindCSS), Hugo invoked the configured Node tools without restrictions on file system access. As a result, executing hugo against an untrusted site could allow code running through these tools to read or write files outside the project's working directory. Users who do not use PostCSS, Babel, or TailwindCSS, or who only build trusted sites, are not affected. This vulnerability is fixed in 0.161.0.
Hugo is a static site generator. From 0.60.0 to before 0.159.2, links and image links in the default markdown to HTML renderer are not properly escaped. Hugo users who trust their Markdown content or have custom render hooks for links and images are not affected. This vulnerability is fixed in 0.159.2.