CVE-2025-43400: 
macOS vulnerability analysis and mitigation

CVE-2025-43400 is a security vulnerability discovered in Apple's FontParser component affecting multiple Apple operating systems including iOS, iPadOS, macOS, and visionOS. The vulnerability was disclosed and patched by Apple on September 29, 2025. The issue affects a wide range of Apple devices including iPhone 11 and later, iPad Pro models, iPad Air 3rd generation and later, and Apple Vision Pro (Apple iOS, Apple macOS, Apple Vision).

The vulnerability is characterized as an out-of-bounds write issue in the FontParser component that was addressed with improved bounds checking. This type of vulnerability occurs when software writes data past the end of the intended buffer, potentially leading to memory corruption (Apple iOS).

When exploited, the vulnerability can lead to unexpected application termination or corrupt process memory through processing of a maliciously crafted font. This affects the stability and security of applications handling font processing across Apple's operating systems (Apple iOS, Apple macOS).

Apple has addressed this vulnerability by implementing improved bounds checking in the FontParser component. The fix is available in iOS 26.0.1, iPadOS 26.0.1, macOS Sequoia 15.7.1, macOS Tahoe 26.0.1, macOS Sonoma 14.8.1, and visionOS 26.0.1. Users are advised to update their devices to the latest available versions (Apple iOS, Apple macOS).