MacOS 11.3.1

macOS 11.3.1 is an update to macOS 11 (Big Sur) that was released on May 3, 2021 by Apple Inc.

Summary
macOS Big Sur 11.3.1 adds security fixes for WebKit, the browser core that underlies Safari, the Apple online store, and other web-connected apps in macOS.

CVE-2021-30663
Discovered by an anonymous researcher, processing of maliciously crafted web content may lead to arbitrary code execution. Apple became aware of a report that this issue may have been actively exploited.

Description of fix: An integer overflow was addressed with improved input validation.

CVE-2021-30665
Discovered by yangkang (@dnpushme), zerokeeper, and bianliang of 360 ATA, processing of maliciously crafted web content may lead to arbitrary code execution. Apple became aware of a report that this issue may have been actively exploited.

Description of fix: A memory corruption issue was addressed with improved state management.