CVE-2025-43245 is a critical security vulnerability identified in Apple macOS operating systems, caused by a downgrade issue in the enforcement of code-signing restrictions. Code-signing is a security mechanism that ensures only trusted and verified applications can access sensitive system resources and user data. The downgrade flaw allows an attacker to bypass these restrictions by forcing the system to accept a less secure or outdated code-signing policy, thereby enabling a malicious or untrusted app to gain unauthorized access to protected user data. This vulnerability 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 requires no user interaction, no privileges, and can be exploited remotely, making it highly dangerous. The CVSS v3.1 base score of 9.8 reflects the vulnerability's critical impact on confidentiality, integrity, and availability, as an attacker can fully compromise user data and system integrity. The underlying weakness is classified under CWE-290, which relates to authentication issues, indicating that the system fails to properly verify the authenticity of code signatures under certain conditions. Although no known exploits have been reported in the wild yet, the potential for exploitation is significant given the ease of attack and the sensitive nature of the data at risk. Apple addressed this issue by strengthening code-signing enforcement to prevent downgrade attacks, thereby restoring the integrity of application authentication mechanisms. Organizations running affected macOS versions are strongly advised to update to the fixed releases to mitigate this threat.

The impact of CVE-2025-43245 is severe for organizations worldwide that rely on macOS systems. Successful exploitation allows attackers to bypass critical security controls and access protected user data, potentially including personal information, credentials, corporate documents, and other sensitive assets. This can lead to data breaches, intellectual property theft, and unauthorized system control. The vulnerability also compromises system integrity and availability, as attackers could manipulate or disrupt system functions. Given that no authentication or user interaction is required, the attack surface is broad, increasing the likelihood of widespread exploitation once weaponized. Organizations in sectors such as finance, healthcare, government, and technology are at heightened risk due to the sensitivity of their data and the strategic value of their systems. The vulnerability could facilitate advanced persistent threats (APTs) and targeted attacks, undermining trust in macOS security. Additionally, the potential for remote exploitation increases risks in remote work environments and cloud-integrated macOS deployments. Failure to patch promptly could result in significant operational disruption, regulatory penalties, and reputational damage.

To mitigate CVE-2025-43245, organizations should immediately deploy the security updates released by Apple in macOS Sequoia 15.6, Sonoma 14.7.7, and Ventura 13.7.7 or later. Beyond patching, organizations should enforce strict application whitelisting and code-signing policies to prevent execution of untrusted or downgraded applications. Monitoring and logging of application code-signing validation failures can help detect attempted exploitation. Network segmentation and limiting macOS device exposure to untrusted networks reduce the attack surface. Employ endpoint detection and response (EDR) solutions capable of identifying anomalous behaviors related to code-signing bypass attempts. Educate users about the risks of installing unverified applications and maintain least privilege principles to minimize potential damage. Regularly audit macOS systems for compliance with security baselines and promptly revoke any certificates or profiles that could be abused for downgrade attacks. Finally, maintain an incident response plan tailored to macOS environments to quickly contain and remediate any exploitation attempts.