Core Telephony. A deserialization issue was addressed through improved validation.

A type confusion issue was addressed with improved state handling. This issue is fixed in iOS 12.5.5, iOS 14.4 and iPadOS 14.4, macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, Security Update 2021-006 Catalina. A malicious application may be able to execute arbitrary code with kernel privileges. Apple is aware of reports that an exploit for this issue exists in the wild.

CoreGraphics. An integer overflow was addressed with improved input validation.

A permissions issue was addressed with improved validation. This issue is fixed in macOS Big Sur 11.4. A malicious application may be able to bypass Privacy preferences. Apple is aware of a report that this issue may have been actively exploited..

A race condition was addressed with improved locking. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4 and iPadOS 14.4. A malicious application may be able to elevate privileges. Apple is aware of a report that this issue may have been actively exploited..

A flaw was found in WebKitGTK.

Impact: Processing maliciously crafted web content may lead to arbitrary code execution. Description: A type confusion issue was addressed with improved state handling.

Reference: https://webkitgtk.org/security/WSA-2021-0002.html