CVE-2025-43245 is a critical security vulnerability affecting Apple macOS operating systems, specifically addressed in macOS Sequoia 15.6, macOS Sonoma 14.7.7, and macOS Ventura 13.7.7. The vulnerability stems from a downgrade issue related to code-signing restrictions. In essence, an attacker could exploit this flaw to bypass the enhanced code-signing protections introduced by Apple, allowing a malicious application to gain unauthorized access to protected user data. The vulnerability does not require any user interaction or privileges, making it remotely exploitable over the network with low attack complexity. The CVSS v3.1 score of 9.8 reflects the critical nature of this flaw, indicating high impact on confidentiality, integrity, and availability. The CWE-290 classification suggests an authentication bypass or improper authentication mechanism is involved. Although no known exploits are currently reported in the wild, the potential for exploitation is significant due to the lack of required privileges and user interaction. The vulnerability could lead to unauthorized disclosure of sensitive user information, manipulation of data, or disruption of system availability, posing a severe threat to affected systems.

For European organizations, this vulnerability poses a substantial risk, especially those relying on Apple macOS devices for business operations, including sectors such as finance, healthcare, government, and critical infrastructure. Unauthorized access to protected user data could lead to data breaches involving personal identifiable information (PII), intellectual property theft, or exposure of confidential business information. The integrity and availability of systems could also be compromised, potentially disrupting business continuity. Given the critical severity and ease of exploitation, attackers could leverage this vulnerability to conduct espionage, ransomware deployment, or data exfiltration campaigns targeting European entities. Compliance with GDPR and other data protection regulations could be jeopardized if sensitive data is exposed, leading to legal and financial repercussions. The vulnerability's presence in multiple recent macOS versions increases the attack surface across organizations that have not yet applied the patches.

European organizations should prioritize immediate patching of all affected macOS systems by upgrading to macOS Sequoia 15.6, Sonoma 14.7.7, or Ventura 13.7.7 or later versions where the vulnerability is fixed. Beyond patching, organizations should implement strict application whitelisting and monitor for unauthorized or suspicious applications attempting to access protected data. Employ endpoint detection and response (EDR) solutions capable of detecting anomalous behavior related to code-signing bypass attempts. Network segmentation can limit the exposure of critical macOS devices to untrusted networks. Regularly audit and review macOS security configurations and code-signing policies to ensure compliance with best practices. Additionally, enforce multi-factor authentication (MFA) for sensitive systems and data access to mitigate potential lateral movement post-exploitation. User awareness training should emphasize the risks of installing untrusted applications. Finally, maintain up-to-date backups to enable recovery in case of data integrity or availability compromise.