Apple recently announced the existence of at least three different exploits that allow an attacker to gain full control of your device that are actively being exploited.
Full control exploitation means an attacker could download data off your device, activate your camera or microphone unexpectedly, or use your device to send malicious messages to others, who could be their intended target.
Users of Apple iPhones and iPads are encouraged to immediately update their devices to the latest version of iOS, 14.4 to protect themselves from exploitation.
Here are a couple articles with more information:
Apple releases iPhone, iPad update to fix ‘actively exploited’ security flaws | USA Today
Apple says iOS 14.4 fixes three security bugs ‘actively exploited’ by hackers | TechCrunch