Same-Site Scripting vulnerability with localhost/127.0.0.1 DNS record

Today I received an email with a warning for a same-site scripting vulnerability on my website. It refers to this article: https://www.acunetix.com/vulnerabilities/web/same-site-scripting/

It’s a common and sensible practice to install records of the form “localhost. IN A 127.0.0.1” into nameserver configurations, bizarrely however, administrators often mistakenly drop the trailing dot, introducing an interesting variation of Cross-Site Scripting (XSS) I call Same-Site Scripting. The missing dot indicates that the record is not fully qualified, and thus queries of the form “localhost.example.com” are resolved. While superficially this may appear to be harmless, it does in fact allow an attacker to cheat the RFC2109 (HTTP State Management Mechanism) same origin restrictions, and therefore hijack state management data.

I’m on the free tier of Cloudflare and not that familiar with DNS records. This records is, as far as I can remember, generated by Cloudflare within my original setup.

Is this something to worry about or, the original report of this issue is from 2008, something that isn’t a problem anymore?

Thanks for you thoughts in advance folks!