Testing conducted by Apple in October 2020 on production 1.4GHz quad-core Intel Core i5–based 13-inch MacBook Pro systems with 8GB of RAM, a 256GB SSD and prerelease macOS Big Sur. Systems tested with a WPA2 Wi-Fi network connection while running on battery power, with display brightness set to 12 clicks from the bottom or 75 per cent. . After installing this update, the build number for Safari 14.0.3 is 14610.4.3.1.7 on macOS Mojave and 15610.4.3.1.7 on macOS Catalina. Information about products not manufactured by Apple, or independent websites not controlled or tested by Apple, is provided without recommendation or endorsement. Update from Catalina or Mojave. Apple suggests that you should have 20GB of free space on your Mac's drive before you install a new version of macOS - although you may not need that much.

About Apple security updates

For our customers' protection, Apple doesn't disclose, discuss, or confirm security issues until an investigation has occurred and patches or releases are available. Recent releases are listed on the Apple security updates page.

Apple security documents reference vulnerabilities by CVE-ID when possible.

For more information about security, see the Apple Product Security page.

Safari 14.0.3*

Released March 8, 2021

WebKit

Available for: macOS Catalina and macOS Mojave

Impact: Processing maliciously crafted web content may lead to arbitrary code execution

Description: A memory corruption issue was addressed with improved validation.

CVE-2021-1844: Clément Lecigne of Google’s Threat Analysis Group, Alison Huffman of Microsoft Browser Vulnerability Research

New Apple Updates Catalina Not Good

* After installing this update, the build number for Safari 14.0.3 is 14610.4.3.1.7 on macOS Mojave and 15610.4.3.1.7 on macOS Catalina.