CVE-2025-43239 is a vulnerability identified in Apple macOS that stems from an out-of-bounds (OOB) access issue classified under CWE-125. The root cause is insufficient bounds checking when the operating system processes certain file types. A malicious actor can craft a specially designed file that, when opened or processed by an application on macOS, triggers this OOB access, leading to unexpected application termination. This termination can disrupt normal operations, causing denial-of-service conditions and potentially exposing sensitive information if the crash leads to memory disclosure. The vulnerability affects multiple recent macOS versions, specifically Sequoia 15.6, Sonoma 14.7.7, and Ventura 13.7.7, indicating a broad impact across currently supported Apple desktop OS versions. The CVSS v3.1 base score is 7.1, reflecting high severity, with vector AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H. This means the attack requires local access (e.g., the user must open the malicious file), low attack complexity, no privileges, and user interaction, with high impact on confidentiality and availability but no impact on integrity. No public exploits have been reported yet, but the presence of a patch indicates Apple has addressed the issue. The vulnerability could be leveraged in targeted attacks or by malware to disrupt macOS applications or exfiltrate sensitive data from memory. The technical fix involves improved bounds checking to prevent OOB access during file processing.

For European organizations, the impact of CVE-2025-43239 can be significant, especially for enterprises relying on macOS for critical operations such as software development, creative industries, and administrative functions. Unexpected application termination can lead to productivity loss, data loss, and potential exposure of sensitive information due to memory handling flaws. The confidentiality impact is high, which raises concerns for organizations handling personal data under GDPR regulations. Availability impact is also high, as critical applications may crash, causing operational disruptions. Although exploitation requires local access and user interaction, phishing or social engineering could be used to trick users into opening malicious files, increasing the risk. The absence of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as attackers often reverse-engineer patches to develop exploits. Organizations with macOS endpoints in their environment must consider this vulnerability in their risk assessments and incident response planning.

1. Immediately apply the security updates released by Apple for macOS Sequoia 15.6, Sonoma 14.7.7, and Ventura 13.7.7 to ensure the vulnerability is patched. 2. Implement strict policies to restrict the opening of files from untrusted or unknown sources, especially email attachments and downloads. 3. Educate users about the risks of opening unexpected or suspicious files and train them to recognize phishing attempts. 4. Employ endpoint protection solutions capable of detecting anomalous application crashes or suspicious file processing behavior on macOS devices. 5. Use application whitelisting and sandboxing where possible to limit the impact of any exploited vulnerability. 6. Monitor logs and system behavior for signs of exploitation attempts, such as repeated app crashes or unusual file access patterns. 7. Maintain regular backups of critical data to mitigate the impact of potential denial-of-service or data loss incidents caused by exploitation.