Search Bar Issue

I noticed I was getting a ton of Soft 404 errors in my Google Webmaster Tools link errors when I checked them I remember when I was monitoring my search terms on my blog these weird codes was getting added to the search bar so what had happened is someone some how linked sites to my blog from adding code inside the search bar hundreds of them so my question is there a way to fix this issue? The added links to my blog through the search bar I never seen that done before thanks.