The current version of iOS is 27.2.1, which was released on November 9, but it is not clear if that update includes a security fix that addresses the issue. Because the issue involves an unauthorized method of software installation, Apple may not address the issue immediately.
How to protect your iPhone from malware
Sideloading apps increases your chances of security risk. Software that is available on the App Store has been vetted for security issues. To minimize the chances of inadvertently installing malware, do not sideload apps on your iPhone and only use apps from the App Store. If you do sideload apps, understand that you have increased your risk.
The easiest task to perform to secure your iPhone is to update the operating system. iOS can be updated in the Settings app by tapping General > Software Update. Apple also has a separate method for installing immediate security patches called Background Security Improvements. It is located in Settings > Privacy & Security, scroll to the bottom to find Background Security Improvements. Macworld has a list of tips for keeping your iPhone secure.