CVE-2025-31240 is a high-severity vulnerability affecting Apple macOS systems that arises when mounting a maliciously crafted Apple Filing Protocol (AFP) network share. AFP is a network protocol primarily used for file services on macOS and legacy Apple devices. The vulnerability is due to insufficient input validation (CWE-20) when processing AFP shares, which can be exploited remotely without any authentication or user interaction. An attacker controlling a malicious AFP share can cause the target macOS system to terminate unexpectedly, resulting in a denial of service (DoS) condition. This can disrupt user operations and potentially cause data loss if the system terminates during critical processes. The issue affects multiple macOS versions prior to the patched releases: macOS Ventura 13.7.6, macOS Sequoia 15.5, and macOS Sonoma 14.7.6. Apple addressed the vulnerability by implementing improved input validation checks to prevent malformed AFP shares from triggering system termination. The CVSS v3.1 base score is 7.5, reflecting a network attack vector with low complexity, no privileges or user interaction required, and a high impact on availability but no impact on confidentiality or integrity. No known exploits are reported in the wild as of the publication date, but the ease of exploitation and network accessibility make this a significant threat to unpatched systems.

For European organizations, this vulnerability poses a significant risk primarily in environments where macOS systems are used and AFP shares are mounted, such as in creative industries, education, and enterprises with mixed Apple device deployments. The ability for an unauthenticated attacker to cause system termination remotely can lead to operational disruptions, loss of productivity, and potential data loss if systems are terminated during critical tasks. While the vulnerability does not directly compromise data confidentiality or integrity, the denial of service impact can affect business continuity and service availability. Organizations relying on AFP for network file sharing should be particularly cautious, as attackers could exploit this vulnerability by setting up malicious AFP shares on compromised or rogue servers. Given the widespread use of macOS in certain sectors across Europe, failure to patch could result in targeted or opportunistic attacks causing interruptions in workflows and potential reputational damage.

European organizations should prioritize updating all macOS systems to the fixed versions: macOS Ventura 13.7.6, macOS Sequoia 15.5, or macOS Sonoma 14.7.6. In addition to patching, organizations should consider the following specific mitigations: 1) Restrict AFP network share mounting to trusted and verified servers only, using network segmentation and access controls to limit exposure. 2) Disable AFP file sharing services if not required, or migrate to more secure and actively maintained protocols such as SMB or NFS with proper authentication and encryption. 3) Monitor network traffic for unusual AFP share mounting attempts, especially from unknown or external IP addresses. 4) Implement endpoint protection solutions capable of detecting abnormal system termination patterns or suspicious network activity related to AFP. 5) Educate users and administrators about the risks of mounting unknown network shares and enforce policies that prevent connecting to untrusted AFP servers. These targeted actions, combined with timely patching, will reduce the attack surface and mitigate the risk of exploitation.