On 3 May 2021 Apple released patches to fix security issues in macOS, iOS, iPadOS and watchOS.

The security issues, affecting the WebKit browser engine that powers Safari and iOS browsing, potentially allowed an attacker to execute their own code by forcing WebKit to process malicious web content, according to Apple’s macOS Big Sur 11.3.1 security update page.

There are two vulnerabilities:

  • A memory corruption flaw (CVE-2021-30665); and
  • an integer overflow issue (CVE-2021-30663).

Which systems are affected?

The following systems and versions are affected, and patches are available:

Recommended actions

We recommend running the system update process on any Apple devices as soon as possible.

If you want to check whether your Apple device already has the updated software version, the following instructions may be helpful: