CVE-2025-43270 is a high-severity vulnerability affecting Apple macOS operating systems, specifically versions prior to macOS Sequoia 15.6, macOS Ventura 13.7.7, and macOS Sonoma 14.7.7, where an application may gain unauthorized access to the local network. The vulnerability stems from insufficient sandbox restrictions, allowing an app with limited privileges to bypass intended access controls and communicate with devices on the local network without explicit user consent or authorization. This represents a violation of the principle of least privilege and compromises network segmentation protections. The CVSS 3.1 base score of 8.8 reflects the vulnerability's significant impact on confidentiality, integrity, and availability, with low attack complexity and only requiring low privileges and no user interaction. The vulnerability is categorized under CWE-284 (Improper Access Control), indicating that the sandboxing mechanism failed to enforce proper access restrictions. Although no known exploits are reported in the wild yet, the potential for exploitation is high given the ease of attack and the critical nature of local network access. This vulnerability could allow malicious apps to perform reconnaissance, lateral movement, or launch further attacks against other devices on the same network, potentially leading to data exfiltration or disruption of network services. Apple has addressed this issue by enhancing sandbox restrictions in the specified macOS versions, mitigating unauthorized local network access by apps.

For European organizations, this vulnerability poses a significant risk, especially for enterprises and institutions relying on macOS devices within their network environments. Unauthorized local network access by compromised or malicious apps can lead to lateral movement within corporate networks, exposing sensitive internal resources, intellectual property, and personal data protected under GDPR. The breach of confidentiality and integrity could result in data leaks, regulatory penalties, and reputational damage. Additionally, availability could be impacted if attackers leverage this access to disrupt network services or deploy ransomware. Sectors with high macOS adoption, such as creative industries, education, and certain government agencies, are particularly vulnerable. The cross-device nature of local networks means that even a single compromised macOS endpoint could jeopardize the security of other connected devices, including IoT and critical infrastructure components. Given the high CVSS score and the potential for stealthy exploitation without user interaction, European organizations must prioritize patching and monitoring to prevent exploitation.

European organizations should implement the following specific mitigation measures: 1) Promptly update all macOS devices to the fixed versions (Sequoia 15.6, Ventura 13.7.7, Sonoma 14.7.7) to ensure the enhanced sandbox restrictions are applied. 2) Enforce strict application vetting policies, allowing only trusted and verified apps to be installed, leveraging Apple’s notarization and MDM (Mobile Device Management) solutions. 3) Utilize network segmentation and zero-trust principles to limit the exposure of sensitive network segments, reducing the impact of any unauthorized local network access. 4) Monitor network traffic for unusual local network communications originating from macOS endpoints, employing anomaly detection tools tailored for local network activity. 5) Educate users about the risks of installing untrusted applications and encourage reporting of suspicious app behavior. 6) Implement endpoint detection and response (EDR) solutions capable of detecting sandbox escape attempts or unauthorized network access on macOS devices. 7) Regularly audit and review local network access permissions and firewall rules on macOS systems to ensure minimal necessary access is granted.