CVE-2025-43245 is a critical security vulnerability identified in Apple macOS that stems from a downgrade issue related to code-signing enforcement. Code-signing is a security mechanism that ensures only trusted and verified applications run on the system. This vulnerability allows an attacker to bypass these protections by exploiting a downgrade flaw, enabling an untrusted or malicious application to access protected user data without requiring any privileges or user interaction. The flaw affects multiple macOS versions prior to the patched releases: macOS Sequoia 15.6, macOS Sonoma 14.7.7, and macOS Ventura 13.7.7. The vulnerability is classified under CWE-290, which relates to authentication issues, highlighting that the system fails to properly verify the authenticity or integrity of the application code. The CVSS 3.1 base score of 9.8 reflects the vulnerability's critical nature, with an attack vector that is network accessible (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and impacts confidentiality, integrity, and availability (C:H/I:H/A:H). Although no exploits have been reported in the wild yet, the potential for unauthorized data access and system compromise is significant. The vulnerability could be leveraged by attackers to steal sensitive user data, manipulate system processes, or disrupt system availability. Apple addressed this issue by implementing additional code-signing restrictions to prevent downgrade attacks, thereby restoring the integrity of the application verification process.

For European organizations, the impact of CVE-2025-43245 is substantial due to the potential unauthorized access to sensitive user and organizational data on macOS devices. This could lead to data breaches involving personal information, intellectual property, or confidential business data, resulting in regulatory non-compliance under GDPR and other data protection laws. The integrity and availability of systems could also be compromised, affecting business operations and trust. Organizations relying heavily on macOS for critical workflows, especially in sectors like finance, healthcare, government, and technology, face increased risk. The vulnerability's ease of exploitation without user interaction or privileges means that attackers could deploy malware or malicious applications remotely or via social engineering to gain access. This elevates the threat landscape for European enterprises, potentially leading to financial losses, reputational damage, and legal consequences. Additionally, the lack of known exploits in the wild suggests a window of opportunity for proactive defense before widespread attacks occur.

European organizations should immediately prioritize updating all macOS devices to the patched versions: Sequoia 15.6, Sonoma 14.7.7, or Ventura 13.7.7. Beyond patching, organizations should enforce strict application code-signing policies, ensuring that only applications signed by trusted developers are allowed to run. Implementing Mobile Device Management (MDM) solutions can help enforce these policies and monitor device compliance. Restricting the installation of applications to those sourced from the Apple App Store or verified enterprise sources reduces exposure to malicious software exploiting this vulnerability. Network segmentation and endpoint detection and response (EDR) tools should be employed to detect anomalous application behavior indicative of exploitation attempts. Regular security awareness training for users about the risks of installing untrusted applications can further reduce risk. Organizations should also review and tighten access controls and audit logs to detect unauthorized data access. Finally, maintaining an incident response plan tailored to macOS environments will enable rapid containment if exploitation occurs.