Yes, you should update all your Apple things immediately

Security means always being prepared
Apple has published a rash of critical security updates for all the key products in its range, stressing the importance of the patch by also issuing security updates for some older versions of Safari.
Why you should update your devices immediately
Apple recommends you install the updates as soon as possible as the vulnerability means a remote attacker can create a specially crafted web page, trick the victim into opening it, trigger memory corruption and execute arbitrary code on the target system.
WebKit is used to power Safari, but if you don’t use Safari as your primary browser you should still install the security patches, as WebKit is also used by other apps, some of which you may use. Mail, App Store and many apps on Mac, iOS and Linux make use of WebKit, which is why you must install the update.
In combination with targeted phishing attacks and behavior based hacks, this makes the threat a significant one, particularly for entities handling complex or confidential information. Phishing attacks have mushroomed during the pandemic and at one point hundreds of malicious fraudulent COVID-19 attacks were registered every day as the disease struck.
[Also read: Security bugs in Apple: How to protect your device]
The NCSC even reported fake sites impersonating the US Centers for Disease Control (CDC). This is the threat landscape were are in, which is why you should update your Apple devices now to protect yourself.
More about the flaw
The CVE-2021-1844 vulnerability was identified by security researchers Clément Lecigne of Google’s Threat Analysis Group and Alison Huffman of Microsoft Browser Vulnerability Research. It’s categorized as being high risk.Apple says this flaw is a memory corruption issue that could lead to arbitrary code execution when processing specially crafted web content. Lecigne also spotted a similar flaw in the Chrome browser, which you should also update.
Update availability
The update is available for devices running iOS 14.4, iPadOS 14.4, macOS Big Sur, and watchOS 7.3.1(Apple Watch Series 3 and later), and as an update to Safari for MacBooks running macOS Catalina and macOS Mojave. Apple also offers a personal digital security guide.
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