This isn’t a security issue; it’s just using the function method incorrectly. It’s a warning because you have WP_DEBUG turned on. If you don’t want to see these warnings or aren’t confident what they mean, you’ll want to read up about PHP’s error reporting and how to interpret them.
Since I bumped into it, I thought it was better to post it as per Andrew Nacin so that @boonebgorges can review it.
… you may be exposing your users to a possible SQL injection vulnerability … Just be sure to send a link to this post to the developer of the theme or plugin referenced in the error. …
Sounds like it is safe to use
Sorry for any confusion @johnjamesjacoby