Update your iPhone instantly. Apple released the updated version iOS 14.4 with fixes to three critical security gaps which are probably known.
Apple hasn't revealed too many details about the errors, except that "they may have already been used". 
A vulnerability can even affect the kernel and an attacker could increase his privilege level (such as becoming an administrator) to cause serious damage to your device or steal your data.
Οι δύο άλλες ευπάθειες επηρεάζουν τη μηχανή απόδοσης WebKit της Apple που τροφοδοτεί το Safari. Επιτρέπουν στους εισβολείς να τρέξουν αυθαίρετο κώδικα που θα μπορούσε να χρησιμοποιηθεί για να σας παρακολουθεί. Δεν γνωρίζουμε εάν αυτό μπορεί να γίνει από απόσταση ή εάν ο εισβολέας χρειάζεται physics access to the device.
Over time, we may learn more about these security holes, but for now it's important to update your iPhone to iOS 14.4 right away.
To do this, follow the path Settings - General - Software Update and download the update.
