CVE-2025-43366 is a vulnerability identified in Apple macOS, specifically related to an out-of-bounds read condition involving the system's coprocessor memory. The flaw arises due to insufficient bounds checking, which allows an application to read memory regions it should not have access to. This vulnerability could potentially enable an attacker-controlled app to disclose sensitive data stored in the coprocessor memory, which may include cryptographic keys, secure enclave data, or other protected information. The issue has been addressed by Apple in macOS Tahoe 26 through improved bounds checking to prevent out-of-bounds memory access. However, the affected versions prior to this patch are unspecified, indicating that the vulnerability could impact multiple macOS releases before Tahoe 26. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet. The vulnerability primarily affects confidentiality, as unauthorized disclosure of coprocessor memory contents could lead to leakage of sensitive information. The exploitation does not appear to require elevated privileges beyond running an application, but it is unclear if user interaction is necessary. The vulnerability does not directly affect system integrity or availability but poses a significant risk to data confidentiality within macOS environments.

For European organizations, this vulnerability could have serious implications, especially for those relying on macOS devices for handling sensitive or regulated data. Disclosure of coprocessor memory could expose cryptographic keys or secure enclave data, potentially undermining encryption protections and exposing confidential information such as credentials, personal data, or intellectual property. This risk is heightened for sectors like finance, healthcare, government, and critical infrastructure where data confidentiality is paramount and compliance with GDPR and other privacy regulations is mandatory. The vulnerability could facilitate targeted espionage or data theft campaigns if exploited by malicious actors. Although no active exploitation is known, the mere presence of this vulnerability increases the attack surface of macOS systems within European enterprises and public sector organizations, potentially leading to reputational damage, regulatory penalties, and operational disruptions if exploited.

European organizations should prioritize updating all macOS devices to macOS Tahoe 26 or later to ensure the vulnerability is patched. Given the unspecified affected versions, organizations should audit their macOS fleet to identify devices running versions prior to Tahoe 26 and schedule immediate upgrades. Additionally, organizations should implement strict application control policies to limit the installation and execution of untrusted or unnecessary applications, reducing the risk of malicious apps exploiting this vulnerability. Employing endpoint detection and response (EDR) solutions capable of monitoring unusual memory access patterns could help detect exploitation attempts. Organizations should also enforce strong user privilege management, ensuring users operate with least privilege to minimize potential damage. Regular security awareness training should include guidance on avoiding suspicious applications and recognizing potential exploitation indicators. Finally, monitoring vendor advisories and threat intelligence feeds for any emerging exploit reports related to CVE-2025-43366 is critical for timely response.