CVE-2025-43402 is a memory corruption vulnerability in Apple macOS identified as CWE-787 (Out-of-bounds Write). This flaw allows a local application with limited privileges (PR:L) to cause unexpected system termination (crashes) or corrupt process memory, which could lead to privilege escalation or arbitrary code execution. The vulnerability does not require user interaction (UI:N), but the attacker must have local access to the system. The CVSS v3.1 base score is 7.8, reflecting high severity due to its impact on confidentiality, integrity, and availability (all rated high). The vulnerability was addressed by Apple in macOS Tahoe 26.1 through improved memory handling techniques that prevent out-of-bounds writes. Although no known exploits are currently reported in the wild, the nature of the flaw suggests that exploitation could allow attackers to disrupt system stability or execute malicious code with elevated privileges. The affected versions are unspecified, but all macOS versions prior to 26.1 are potentially vulnerable. This vulnerability is particularly concerning for environments where macOS devices are used for sensitive or critical operations, as it could be leveraged for local privilege escalation or denial of service.

For European organizations, this vulnerability poses a significant risk especially in sectors where macOS devices are prevalent, such as creative industries, education, and certain government agencies. The ability for a local app to corrupt memory or cause system crashes can lead to data breaches, loss of system availability, and potential lateral movement if exploited for privilege escalation. Confidentiality is at risk due to possible memory corruption leading to data leakage. Integrity is compromised as process memory corruption can alter application behavior or system processes. Availability is impacted through unexpected system termination, potentially disrupting business operations. Organizations with remote or hybrid work models using macOS endpoints are particularly vulnerable if local attackers gain access through compromised accounts or insider threats. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, as proof-of-concept exploits could emerge. Failure to patch promptly could expose organizations to targeted attacks or malware leveraging this vulnerability.

The primary mitigation is to upgrade all macOS systems to version Tahoe 26.1 or later, where the vulnerability is fixed. Organizations should enforce strict patch management policies to ensure timely deployment of security updates. Employ application whitelisting to restrict execution of unauthorized or untrusted applications that could exploit this flaw. Utilize endpoint detection and response (EDR) solutions capable of monitoring for anomalous memory corruption or process crashes. Implement least privilege principles to limit the ability of local applications to perform sensitive operations. Regularly audit installed software and running processes to detect suspicious activity. For environments where immediate patching is not feasible, consider isolating macOS devices or restricting local user permissions to reduce exploitation risk. Educate users about the risks of running untrusted applications and maintain robust backup and recovery procedures to minimize impact from potential system crashes or data corruption.