CVE-2025-24191 is a vulnerability in Apple macOS identified as a weakness in the validation of environment variables, which allows an application to modify protected parts of the file system. The vulnerability stems from improper input validation (classified under CWE-20), where environment variables are not sufficiently sanitized before being used in operations affecting critical system areas. This flaw can be exploited by a local attacker who does not require privileges but does require user interaction, such as convincing a user to run a malicious application. The attacker could leverage this to alter system files that are normally protected, potentially leading to integrity violations such as unauthorized code execution or persistence mechanisms. The vulnerability affects macOS versions prior to Sequoia 15.4, where Apple has implemented improved validation of environment variables to mitigate the issue. The CVSS v3.1 base score is 5.5 (medium severity), reflecting that the attack vector is local (AV:L), with low attack complexity (AC:L), no privileges required (PR:N), but user interaction is necessary (UI:R). The impact is limited to integrity (I:H) with no confidentiality or availability impact. No known exploits have been reported in the wild as of the publication date. This vulnerability highlights the importance of environment variable validation in operating system security and the risks posed by local applications with insufficient sandboxing or privilege restrictions.

For European organizations, the primary impact of CVE-2025-24191 lies in the potential compromise of system integrity on macOS devices. Organizations relying on Apple hardware for critical operations—such as creative industries, software development, or executive environments—may face risks of unauthorized modification of system files, which could lead to persistent malware, unauthorized code execution, or bypass of security controls. Although the vulnerability does not directly affect confidentiality or availability, integrity breaches can facilitate further attacks or data manipulation. The requirement for local access and user interaction limits remote exploitation but does not eliminate risk, especially in environments where users may install untrusted software or where endpoint security controls are lax. Given the widespread use of macOS in certain European markets, failure to patch could expose organizations to targeted attacks or insider threats exploiting this vulnerability. Additionally, sectors with stringent compliance requirements (e.g., finance, healthcare) must consider the integrity risks as part of their security posture.

To mitigate CVE-2025-24191, European organizations should prioritize updating all macOS systems to version Sequoia 15.4 or later, where the vulnerability has been addressed through improved environment variable validation. Organizations should enforce strict application whitelisting and restrict installation of software from untrusted sources to reduce the risk of malicious applications exploiting this flaw. Endpoint protection solutions should be configured to detect suspicious local activities and monitor for unauthorized modifications to protected file system areas. User awareness training is critical to prevent inadvertent execution of malicious applications requiring user interaction. Additionally, implementing least privilege principles and sandboxing applications can limit the potential impact of local exploits. Regular vulnerability scanning and compliance checks should include verification of macOS patch levels. For environments with high security requirements, consider deploying macOS security features such as System Integrity Protection (SIP) and Endpoint Security Framework to further harden systems against unauthorized modifications.