iOS 14.4.2 and iPadOS 14.4.2
iOS 14.4.2 is a security update available for: iPhone 6s and later, iPad Pro (all models), iPad Air 2 and later, iPad 5th generation and later, iPad mini 4 and later, and iPod touch (7th generation)

TL:DR— Install right away. Security fixes.
Step by step instructions
- Open 'Software Update' from 'Settings -> General'
- Download and install, a restart is required and it takes some time


Security Fixes
- Available for: iPhone 5s, iPhone 6, iPhone 6 Plus, iPad Air, iPad mini 2, iPad mini 3, and iPod touch (6th generation)
- Impact: Processing maliciously crafted web content may lead to universal cross site scripting. Apple is aware of a report that this issue may have been actively exploited.
- Description: This issue was addressed by improved management of object lifetimes.
- CVE-2021-1879: Clement Lecigne of Google Threat Analysis Group and Billy Leonard of Google Threat Analysis Group
Confirming the iPhone, iPod touch or iPad has been updated
- Navigate to 'Settings'
- Select 'General'
- Select About
- Software Version will be '12.5.2'
See also: About the security content of iOS 12.5.2