CVE-2025-43270 is a vulnerability in Apple macOS that allows an application with limited privileges to bypass sandbox restrictions and gain unauthorized access to the Local Network. The root cause is an access control weakness (CWE-284) where sandbox policies did not sufficiently restrict network access for certain apps, enabling them to interact with local network resources without proper authorization. This could allow malicious or compromised applications to perform unauthorized network reconnaissance, intercept local traffic, or attempt lateral movement within a local network environment. The vulnerability affects macOS versions prior to Sequoia 15.6, Ventura 13.7.7, and Sonoma 14.7.7, where Apple has implemented additional sandbox restrictions to mitigate the issue. The CVSS 3.1 base score of 8.8 indicates a high severity, with the vector AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H meaning the attack requires local access with low complexity and limited privileges, no user interaction, and impacts confidentiality, integrity, and availability with scope change. No known exploits have been reported in the wild as of the publication date. The vulnerability highlights the importance of strict sandbox enforcement and network access controls in modern operating systems to prevent privilege escalation and lateral movement by malicious apps.

For European organizations, this vulnerability poses a significant risk due to the widespread use of Apple macOS devices in enterprise environments, including government, finance, healthcare, and technology sectors. Unauthorized local network access by a malicious app could lead to data exfiltration, interception of sensitive communications, or compromise of other networked systems through lateral movement. This could result in breaches of confidentiality, integrity, and availability of critical systems and data. The vulnerability's low complexity and lack of required user interaction increase the likelihood of exploitation once a malicious app is installed. Organizations with less mature application vetting processes or those that allow installation of third-party or internally developed apps without strict controls are particularly vulnerable. Additionally, the potential for scope change means that an initially limited local compromise could escalate to broader network impact, amplifying the damage. The absence of known exploits in the wild provides a window for proactive mitigation, but the high CVSS score underscores the urgency of patching and defense-in-depth strategies.

1. Immediately update all macOS devices to the fixed versions: Sequoia 15.6, Ventura 13.7.7, or Sonoma 14.7.7, as applicable. 2. Enforce strict application vetting policies to prevent installation of untrusted or unsigned apps, including internal app review and use of Apple’s notarization services. 3. Implement network segmentation to limit the impact of any local network access gained by compromised devices or apps. 4. Utilize endpoint protection solutions capable of monitoring and restricting unusual local network activities initiated by user-level applications. 5. Educate users about the risks of installing unauthorized software and encourage reporting of suspicious app behavior. 6. Regularly audit installed applications and their network permissions to detect and remediate risky configurations. 7. Employ macOS security features such as System Integrity Protection (SIP) and Application Firewall to reduce attack surface. 8. Monitor network traffic for anomalous patterns that could indicate lateral movement or unauthorized local network scanning. 9. Maintain an incident response plan that includes procedures for local network compromise scenarios involving macOS devices.