CVE-2025-43355 is a vulnerability classified under CWE-843 (Type Confusion) affecting Apple’s macOS and other Apple operating systems such as iOS, iPadOS, tvOS, watchOS, and visionOS. The root cause is improper memory handling that leads to type confusion, where an application incorrectly interprets the type of an object or data structure in memory. This can cause unexpected behavior, including crashes or denial-of-service conditions. The vulnerability allows a local application, requiring user interaction but no elevated privileges, to trigger a denial-of-service by exploiting this memory mismanagement. The CVSS v3.1 score is 5.5 (medium severity), reflecting the local attack vector (AV:L), low complexity (AC:L), no privileges required (PR:N), user interaction required (UI:R), unchanged scope (S:U), no impact on confidentiality or integrity (C:N/I:N), but high impact on availability (A:H). The issue was addressed by Apple in their September 2025 security updates across multiple OS versions, including macOS Sonoma 14.8 and Sequoia 15.7. No public exploit code or active exploitation has been reported, but the vulnerability poses a risk of service disruption if exploited. This vulnerability highlights the importance of robust memory management in preventing denial-of-service attacks and maintaining system stability.

For European organizations, the primary impact of CVE-2025-43355 is on system availability. A successful exploitation can cause macOS devices to crash or become unresponsive, potentially disrupting business operations, especially in environments relying heavily on Apple hardware and software. Sectors such as finance, healthcare, and government agencies that use macOS for critical tasks could face operational downtime, impacting productivity and service delivery. Although the vulnerability does not compromise confidentiality or integrity, the denial-of-service effect could be leveraged in targeted attacks to interrupt workflows or as part of a larger attack chain. The requirement for local access and user interaction limits remote exploitation but does not eliminate risk from insider threats or social engineering attacks. Organizations with mixed-device environments must ensure Apple systems are patched to prevent this vulnerability from becoming an entry point for disruption.

European organizations should implement the following specific mitigations: 1) Deploy the latest Apple security updates immediately, specifically macOS Sonoma 14.8, macOS Sequoia 15.7, and corresponding updates for iOS, iPadOS, tvOS, watchOS, and visionOS to remediate the vulnerability. 2) Enforce strict application control policies to limit installation and execution of untrusted or unnecessary local applications that could exploit this vulnerability. 3) Educate users on the risks of interacting with untrusted applications or links that may trigger the vulnerability. 4) Monitor macOS systems for abnormal crashes or service interruptions that could indicate exploitation attempts. 5) Employ endpoint detection and response (EDR) tools capable of detecting anomalous behavior related to memory corruption or application crashes. 6) For critical environments, consider network segmentation and limiting physical or remote access to macOS devices to reduce the attack surface. 7) Maintain regular backups and incident response plans to quickly recover from potential denial-of-service incidents.