CVE-2021-1742: 
macOS vulnerability analysis and mitigation

CVE-2021-1742 is a security vulnerability affecting Apple's ImageIO component that was disclosed and patched in January 2021. The vulnerability was discovered by Xingwei Lin of Ant Security Light-Year Lab and affects multiple Apple operating systems including macOS Big Sur, iOS 14.4, iPadOS 14.4, watchOS 7.3, and tvOS 14.4. Processing a maliciously crafted image may lead to arbitrary code execution (Apple Security).

The vulnerability exists in the ImageIO component and is triggered when processing maliciously crafted images. This issue was addressed with improved checks in the affected systems. The vulnerability was 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 (Apple Security).

When exploited, the vulnerability allows processing of a maliciously crafted image to lead to arbitrary code execution on the affected system (Apple Security).

The vulnerability requires processing a maliciously crafted image to be exploited. No information about active exploitation in the wild was reported by Apple in their security advisories (Apple Security).

Apple addressed this vulnerability by implementing improved checks in the ImageIO component. Users should update to macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4 or iPadOS 14.4 to receive the fix (Apple Security).