Query injection vector issue

Hi, I’m having a problem in my WordPress website silviagirao.com.br.

The site seems to be vulnerable to some kind of exploit.

The host sent me a report that says this:

Query injection vector (2)

https://silviagirao.com.br/index.php?cat=3%200%200%20-%20- [ show trace + ]
Memo: response suggests arithmetic evaluation on server side (type 2)

https://silviagirao.com.br/?feed=rss2&cat=3%200%200%20-%20- [ show trace + ]
Memo: response suggests arithmetic evaluation on server side (type 2)

Any idea how to correct this?