CVE-2025-31246 is a vulnerability in the Apple Filing Protocol (AFP) client implementation within macOS that allows a remote attacker to corrupt kernel memory by connecting to a malicious AFP server. The root cause is improper memory handling, classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). When a macOS device connects to a compromised or attacker-controlled AFP server, crafted responses can trigger memory corruption in the kernel space, potentially leading to arbitrary code execution with kernel privileges. The vulnerability requires network access to the AFP service and low privileges (PR:L), but no user interaction (UI:N) is necessary, making it easier to exploit in targeted attacks. The scope is unchanged (S:U), meaning the impact is limited to the vulnerable system. The CVSS v3.1 base score is 8.8, reflecting high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). Apple addressed the issue in macOS Sequoia 15.5 and Sonoma 14.7.6 by improving memory handling in the AFP client. Although no public exploits are known, the vulnerability poses a significant risk due to the potential for kernel-level compromise, which could allow attackers to bypass security controls, install persistent malware, or disrupt system operations. Organizations using AFP or allowing AFP traffic should consider this vulnerability critical and apply patches promptly.

For European organizations, this vulnerability poses a significant threat, especially those with macOS devices connected to internal or external AFP servers. Successful exploitation can lead to full kernel compromise, allowing attackers to execute arbitrary code with the highest privileges, potentially leading to data theft, system disruption, or persistent backdoors. Confidentiality of sensitive information stored or accessed on macOS devices can be compromised, and system integrity and availability may be severely impacted. Sectors such as finance, government, healthcare, and critical infrastructure that rely on Apple devices for daily operations are at particular risk. Additionally, organizations using AFP for file sharing or legacy systems may inadvertently expose themselves to attacks. The lack of required user interaction increases the risk of automated or stealthy exploitation attempts. Although no known exploits are currently in the wild, the high severity and ease of exploitation warrant immediate attention to prevent potential targeted attacks or future exploitation campaigns.

1. Immediately apply the security updates provided by Apple in macOS Sequoia 15.5 and Sonoma 14.7.6 or later versions to all affected macOS devices. 2. Disable AFP file sharing services on macOS devices if not required, or restrict AFP network access using firewalls or network segmentation to limit exposure to untrusted networks. 3. Monitor network traffic for unusual AFP connection attempts, especially from unknown or external IP addresses, to detect potential reconnaissance or exploitation attempts. 4. Employ endpoint detection and response (EDR) solutions capable of detecting anomalous kernel-level activity or memory corruption indicators on macOS devices. 5. Educate IT and security teams about the risks of legacy protocols like AFP and encourage migration to more secure file sharing protocols such as SMB or NFS with proper authentication and encryption. 6. Conduct regular vulnerability assessments and penetration tests focusing on macOS environments to identify residual risks related to AFP or other legacy services. 7. Maintain an inventory of macOS devices and their patch levels to ensure timely updates and compliance with security policies.