Today, I came to read about this blog. There seems to be a security issue if you are using SQL logins, but Microsoft says it is not an issue to worry about it. According to this post, Microsoft will not issue a security patch to resolve this problem.
Are you worried about this? You can read this article where it shows how things can go wrong and ways to prevent them.
Is SQL Server's latest security hole a real threat?test-security-hole-real-threat-801