CVE-2025-43255 is a vulnerability identified in Apple macOS operating systems that allows an application to cause unexpected system termination due to an out-of-bounds read condition. An out-of-bounds read occurs when a program reads data outside the boundaries of allocated memory, which can lead to undefined behavior including crashes or system instability. In this case, the vulnerability could be exploited by a malicious or compromised app to trigger a system crash, resulting in a denial of service (DoS) condition. Apple has addressed this issue by implementing improved bounds checking in the affected components. The vulnerability affects multiple macOS versions, including macOS Sonoma 14.7.7, macOS Sequoia 15.6, and macOS Ventura 13.7.7, where the fix has been applied. The exact affected versions prior to these patched releases are unspecified. There are no known exploits in the wild at the time of publication. The vulnerability does not require elevated privileges or authentication but does require that a malicious app be executed on the system. This implies that user interaction or prior compromise to run the malicious app is necessary. The absence of a CVSS score suggests that the vulnerability is recognized but not yet fully scored, likely due to limited impact or exploitability. The primary risk is denial of service through system crashes, which can disrupt user productivity and potentially cause data loss if unsaved work is lost during unexpected termination. The vulnerability does not appear to allow code execution or privilege escalation directly but could be leveraged as part of a more complex attack chain.

For European organizations, the impact of CVE-2025-43255 primarily revolves around availability disruption. Enterprises relying on macOS devices for critical operations may experience unexpected system crashes, leading to downtime and potential loss of productivity. This can be particularly impactful in sectors such as finance, healthcare, and government services where macOS is used for sensitive or mission-critical tasks. Although the vulnerability does not directly compromise confidentiality or integrity, repeated or targeted exploitation could degrade trust in system stability and increase operational risk. Organizations with large macOS deployments may face increased helpdesk and IT support burdens due to system instability. Additionally, if exploited in conjunction with other vulnerabilities, it could facilitate more severe attacks. The lack of known exploits reduces immediate risk, but the presence of the vulnerability in widely used macOS versions means that organizations should proactively address it to maintain system reliability and security posture.

To mitigate CVE-2025-43255, European organizations should prioritize updating all macOS systems to the patched versions: macOS Sonoma 14.7.7, macOS Sequoia 15.6, or macOS Ventura 13.7.7. Since the vulnerability requires execution of a malicious app, organizations should enforce strict application control policies, including the use of Apple’s Gatekeeper and notarization requirements to prevent untrusted apps from running. Endpoint protection solutions with behavior-based detection can help identify suspicious app activity that might attempt to exploit this vulnerability. Regular user training on the risks of running untrusted software will reduce the likelihood of exploitation. Additionally, implementing network segmentation and least privilege principles can limit the impact if a device is compromised. Monitoring system logs for unexpected crashes and correlating with application activity can provide early warning signs of exploitation attempts. Finally, organizations should maintain robust backup and recovery procedures to minimize data loss from unexpected system terminations.