A site’s search results pages are generated via a user request. The problem is that anyone can generate this kind of pages simply via a link. Indirectly, you allow everyone to create content on your site.
Consequence: many spammers use this hack which brings it up in Google Search Console.
To try to prevent this phenomenon, you can block the indexing of search results pages from your WordPress administration, SEO, Titles and metas, Archives, Search archives and check noindex.
Save changes then clear your cache.
This should help at least search engines to index these pages in their search results.