CVE-2025-43254 is a high-severity vulnerability affecting Apple macOS operating systems, specifically versions prior to macOS Sequoia 15.6, macOS Ventura 13.7.7, and macOS Sonoma 14.7.7. The vulnerability arises from an out-of-bounds read condition (CWE-125) due to insufficient input validation when processing certain file types. An attacker can craft a malicious file that, when opened or processed by a vulnerable macOS application, triggers this out-of-bounds read, leading to unexpected application termination (crash). The CVSS 3.1 base score is 7.1, indicating a high severity level. The vector string (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H) reveals that exploitation requires local access (AV:L), low attack complexity (AC:L), no privileges (PR:N), and user interaction (UI:R). The scope is unchanged (S:U), with high confidentiality impact (C:H), no integrity impact (I:N), and high availability impact (A:H). Although no known exploits are currently reported in the wild, the vulnerability could be leveraged by attackers to cause denial-of-service conditions by crashing applications that process maliciously crafted files. This could disrupt user workflows and potentially be used as part of a larger attack chain. The vulnerability affects macOS systems broadly, but the exact affected versions are unspecified beyond the fixed releases. The root cause is an out-of-bounds read, which can lead to memory disclosure or application instability. Apple has addressed the issue by improving input validation in the affected components.

For European organizations, this vulnerability poses a significant risk primarily in terms of availability and confidentiality. The high confidentiality impact suggests that sensitive data could potentially be exposed due to the out-of-bounds read, although no integrity impact is noted. Unexpected application termination can disrupt business operations, especially in environments relying heavily on macOS for critical workflows such as creative industries, software development, and administrative functions. Organizations with large macOS deployments may experience increased support and downtime costs. Additionally, the requirement for local access and user interaction means that social engineering or phishing campaigns could be used to trick users into opening malicious files, potentially leading to targeted denial-of-service attacks or information leakage. This is particularly concerning for sectors handling sensitive personal or corporate data under GDPR regulations, where data confidentiality breaches can result in regulatory penalties. The absence of known exploits in the wild reduces immediate risk but does not eliminate the threat, as attackers may develop exploits once the vulnerability details are public. Therefore, European organizations should prioritize patching to mitigate potential exploitation.

1. Immediate deployment of the security updates provided by Apple for macOS Sequoia 15.6, Ventura 13.7.7, and Sonoma 14.7.7 is critical. Ensure all macOS systems are updated to these or later versions. 2. Implement strict file handling policies that restrict opening files from untrusted or unknown sources, especially in environments with sensitive data. 3. Educate users about the risks of opening unsolicited or suspicious files, emphasizing the need for caution with email attachments and downloads. 4. Employ endpoint protection solutions capable of detecting anomalous application crashes or suspicious file processing behaviors to provide early warning of exploitation attempts. 5. Use application whitelisting and sandboxing techniques to limit the impact of any application crashes and prevent lateral movement. 6. Regularly audit and monitor macOS systems for unusual activity or crashes that could indicate attempted exploitation. 7. For organizations with macOS in critical roles, consider network segmentation to isolate vulnerable systems and reduce the attack surface. 8. Maintain backups and incident response plans to quickly recover from potential denial-of-service incidents caused by exploitation.