iOS 13.1.3
iOS 13.1.3 includes bug fixes and improvements for your iPhone. This update:
• Addresses an issue that could prevent a device from ringing or vibrating for an incoming call
• Fixes an issue that may prevent opening a meeting invite in Mail
• Resolves an issue where data in the Health app may not display correctly after daylight savings time adjusts
• Fixes an issue where Voice Memos recordings may not download after restoring from iCloud Backup
• Addresses an issue where apps might fail to download when restoring from iCloud Backup
• Fixes an issue that can prevent Apple Watch from pairing successfully
• Resolves an issue where notifications may not be received on Apple Watch
• Fixes an issue where Bluetooth may disconnect on certain vehicles
• Improves connection reliability of Bluetooth hearing aids and headsets
• Addresses launch performance for apps that use Game Center
For information on the security content of Apple software updates, please visit this website: https://support.apple.com/kb/HT201222
Honestly, this information is just a search away. Most of the updates mentioned in this version are not directly related to fixing any such vulnerabilities/exploits as you mentioned. In such events, major security patches are usually deployed in a short span of time.
It is not dangerous to use your current version but I recommend you to use the latest version software when possible.
Even though some of the new features may not prove to be necessary, sometimes the small bug fixes/security patches can save you a lot of trouble in case of any unfortunate security breaches.