Yes. Vulnerabilities aren’t strictly form-related; there are many avenues.
Platforms like WordPress and Drupal serve via an application layer, which means any insecure code in the core platform or in plugins is theoretically available to exploit. That’s fairly simplified, but more or less accurate. Do not run WordPress or Drupal yourself unless you are able to keep them updated.
“Static” sites typically use an application to generate the HTML/etc for a site. This is typically an application like Jekyll or Hugo, but it actually could be WordPress or Drupal provided you generate fully rendered HTML, and that is what the end user sees. In these cases, the only application the end user is interacting with is a web server - usually Apache or nginx - and so your only vulnerabilities would be in those web servers, which are well maintained and don’t have many vulnerable surfaces.
(I run a decent sized Drupal platform serving multiple sites for an internet company you have probably heard of.)