CVE-2025-43359 is a critical logic vulnerability identified in Apple’s macOS and other Apple operating systems that handle UDP server sockets. The issue arises from improper state management in the socket binding process, where a UDP server socket that is intended to bind exclusively to a local interface may instead become bound to all network interfaces on the device. This unintended binding expands the attack surface by exposing the UDP service beyond the intended local scope, potentially allowing remote attackers to send malicious UDP packets to services that should have been restricted. The vulnerability affects multiple Apple OS versions, including macOS Sonoma 14.8, macOS Sequoia 15.7, iOS 26, iPadOS 26, tvOS 26, watchOS 26, and visionOS 26. The flaw is categorized under CWE-670 (Improper Resource Shutdown or Release), indicating a failure in managing socket states correctly. The CVSS v3.1 base score is 9.8 (critical), with vector AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, meaning the vulnerability can be exploited remotely over the network with no privileges or user interaction required, and can lead to complete compromise of confidentiality, integrity, and availability of affected systems. While no known exploits have been reported in the wild yet, the severity and ease of exploitation make it a critical concern. The vulnerability could be leveraged to intercept, manipulate, or disrupt network communications on affected Apple devices, impacting both personal and enterprise environments. Apple has addressed the issue with improved state management in the socket binding process in the latest OS updates, but affected versions prior to these patches remain vulnerable.

For European organizations, the impact of CVE-2025-43359 can be significant, especially for those heavily reliant on Apple hardware and software ecosystems. The vulnerability could allow attackers to remotely access UDP services that were intended to be locally scoped, potentially leading to unauthorized data access, interception of sensitive communications, or denial of service conditions. This can compromise confidentiality, integrity, and availability of critical applications and services running on Apple devices. Enterprises using macOS or iOS devices for internal communications, network services, or IoT management could see increased risk of lateral movement or network reconnaissance by attackers. The exposure of UDP services across all interfaces could also facilitate exploitation by malware or advanced persistent threat (APT) actors targeting European critical infrastructure, government agencies, or financial institutions. Given the critical CVSS score and the lack of required authentication or user interaction, the threat is highly exploitable and could lead to widespread disruption if not mitigated promptly.

1. Apply patches and updates immediately once Apple releases them for the affected operating systems (macOS Sonoma 14.8, macOS Sequoia 15.7, iOS 26, iPadOS 26, tvOS 26, watchOS 26, visionOS 26). 2. Until patches are applied, restrict UDP traffic at network boundaries using firewalls or network segmentation to limit exposure of UDP services to trusted interfaces only. 3. Implement strict network monitoring and anomaly detection focused on unusual UDP traffic patterns that could indicate exploitation attempts. 4. Review and harden configurations of applications and services using UDP sockets to ensure they do not rely on default binding behavior and explicitly specify interface bindings where possible. 5. Employ endpoint security solutions capable of detecting suspicious socket behavior or unauthorized network bindings. 6. Educate IT and security teams about this vulnerability to ensure rapid response and incident handling. 7. For organizations using Apple devices in critical roles, consider temporary isolation or additional network controls until full remediation is confirmed.