CVE-2025-43296 is a logic flaw in Apple macOS's Gatekeeper mechanism, which is responsible for validating and restricting the execution of untrusted applications to protect users from malware and unauthorized software. The vulnerability arises from insufficient validation checks within Gatekeeper, allowing an application to bypass these security controls. This bypass means that malicious or unverified applications can run on the system without triggering Gatekeeper's warnings or blocks, effectively undermining a core macOS security feature. The vulnerability was addressed and fixed in the macOS Tahoe 26 release, which includes improved validation logic to prevent such bypasses. The affected versions prior to this update are unspecified, but all macOS versions before Tahoe 26 should be considered vulnerable. There are currently no known exploits in the wild, indicating that attackers have not yet leveraged this flaw publicly. However, the potential for exploitation exists, especially by threat actors targeting macOS users. The lack of a CVSS score necessitates a severity assessment based on the nature of the vulnerability: it impacts system integrity by allowing unauthorized code execution, requires no authentication or user interaction, and affects a widely used operating system in enterprise and personal environments. Gatekeeper is a fundamental security control in macOS, so bypassing it significantly raises the risk profile for affected systems. Organizations relying on macOS devices should consider this a high-risk vulnerability until patched.

For European organizations, the ability to bypass Gatekeeper checks can lead to the execution of malicious software that would otherwise be blocked, increasing the risk of malware infections, data breaches, and unauthorized system modifications. This vulnerability compromises the integrity and potentially the confidentiality of affected systems by allowing untrusted code to run without detection. Organizations with macOS endpoints, especially those in sectors with sensitive data such as finance, healthcare, and government, face elevated risks of targeted attacks leveraging this flaw. The absence of user interaction or authentication requirements means that attackers can exploit this vulnerability remotely or through social engineering with minimal barriers. The impact extends to supply chain security, as malicious apps could be introduced into enterprise environments unnoticed. Additionally, the potential for lateral movement within networks increases if attackers gain footholds on macOS devices. The overall availability of systems could also be affected if malware disables critical services or causes system instability. European organizations must therefore prioritize patching and monitoring to mitigate these risks.

1. Immediately upgrade all macOS devices to macOS Tahoe 26 or later, which contains the fix for this vulnerability. 2. Implement application whitelisting policies to restrict execution to only trusted and verified software, reducing the risk of malicious app execution. 3. Enhance endpoint detection and response (EDR) capabilities to monitor for unusual application behaviors that may indicate Gatekeeper bypass attempts. 4. Educate users on the risks of installing software from untrusted sources and enforce strict controls on software installation privileges. 5. Regularly audit and inventory macOS devices to ensure compliance with patching policies and identify any unpatched systems. 6. Use network segmentation to limit the impact of compromised macOS devices and prevent lateral movement. 7. Monitor security advisories from Apple and threat intelligence sources for updates on exploitation attempts or new mitigations. 8. Consider deploying additional macOS security tools that provide runtime protection and behavioral analysis to detect exploitation attempts.