CVE-2025-31246 is a critical memory corruption vulnerability in the Apple Filing Protocol (AFP) client component of macOS. The vulnerability arises due to improper memory handling when the system connects to a malicious AFP server. AFP is a network protocol used primarily for file services on macOS systems. An attacker controlling a malicious AFP server can exploit this flaw by enticing a vulnerable macOS client to connect, triggering kernel memory corruption. This corruption can lead to arbitrary code execution at the kernel level, allowing an attacker to gain full control over the affected system, compromising confidentiality, integrity, and availability. The vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), indicating a classic buffer overflow or similar memory safety issue. The CVSS v3.1 score of 8.8 reflects its high severity, with an attack vector of network (AV:N), low attack complexity (AC:L), requiring low privileges (PR:L), no user interaction (UI:N), and impacting confidentiality, integrity, and availability at a high level (C:H/I:H/A:H). Apple fixed this issue in macOS Sequoia 15.5 and macOS Sonoma 14.7.6 by improving memory handling in the AFP client. No public exploits have been reported yet, but the potential for kernel-level compromise makes this a critical vulnerability to address promptly.

The impact of CVE-2025-31246 is severe for organizations using vulnerable macOS versions. Successful exploitation allows attackers to execute arbitrary code with kernel privileges, effectively taking full control of the system. This can lead to data theft, system manipulation, installation of persistent malware, and disruption of services. Since the vulnerability affects kernel memory, it can bypass many security controls and sandboxing mechanisms, making detection and mitigation post-exploitation difficult. Enterprises relying on macOS for critical operations, especially those using AFP for file sharing, face risks of targeted attacks or lateral movement within networks. The lack of required user interaction and the network attack vector increase the likelihood of exploitation in automated or targeted campaigns. Although no exploits are known in the wild yet, the vulnerability’s characteristics make it a prime candidate for future exploitation, potentially impacting confidentiality, integrity, and availability of affected systems globally.

Organizations should immediately upgrade affected macOS systems to versions macOS Sequoia 15.5 or macOS Sonoma 14.7.6 or later, where the vulnerability is patched. Until patching is possible, restrict or disable AFP protocol usage, especially connections to untrusted or external AFP servers, to reduce exposure. Network segmentation and firewall rules should be employed to limit AFP traffic to trusted internal sources only. Monitoring network traffic for unusual AFP connection attempts can help detect potential exploitation attempts. Additionally, implement endpoint detection and response (EDR) solutions capable of identifying kernel-level anomalies or suspicious behavior indicative of exploitation. Regularly audit macOS systems for compliance with patch levels and AFP usage policies. Educate users and administrators about the risks of connecting to unknown AFP servers. Finally, consider transitioning to more secure file sharing protocols where feasible, as AFP is legacy and less commonly used in modern environments.