CVE-2025-24191 is a vulnerability in Apple macOS that allows an application to modify protected parts of the file system due to improper validation of environment variables. Specifically, the flaw arises from insufficient checks on environment variables that an app can influence, which can be leveraged to bypass protections on critical system files and directories. This vulnerability affects macOS versions prior to Sequoia 15.4, where Apple implemented improved validation mechanisms to mitigate the issue. The vulnerability is classified under CWE-20 (Improper Input Validation), indicating that the system fails to properly validate input data, leading to unauthorized modification capabilities. The CVSS v3.1 score is 5.5 (medium severity), with the vector indicating local attack vector (AV:L), low attack complexity (AC:L), no privileges required (PR:N), user interaction required (UI:R), unchanged scope (S:U), no confidentiality impact (C:N), high integrity impact (I:H), and no availability impact (A:N). This means an attacker must have local access and trick a user into interacting with a malicious app to exploit the vulnerability. While confidentiality and availability are unaffected, the integrity of the system is at high risk because protected file system areas can be altered, potentially leading to persistent compromise or further privilege escalation. No known exploits are currently reported in the wild, but the vulnerability presents a significant risk if weaponized. The issue was reserved in January 2025 and published in March 2025, indicating recent discovery and patching. Organizations using macOS should update to Sequoia 15.4 or later to remediate this vulnerability.

The primary impact of CVE-2025-24191 is on system integrity, as it allows an unprivileged application to modify protected parts of the macOS file system. This could enable attackers to implant persistent malware, alter system binaries, or manipulate security configurations, potentially leading to privilege escalation or persistent backdoors. Although confidentiality and availability are not directly affected, the integrity compromise can indirectly lead to data breaches or system instability. The requirement for local access and user interaction limits remote exploitation but does not eliminate risk, especially in environments where users may install untrusted applications or open malicious files. Organizations relying on macOS for critical operations, software development, or sensitive data processing could face operational disruptions and increased risk of targeted attacks. The absence of known exploits in the wild suggests limited immediate threat, but the vulnerability's nature means it could be leveraged in targeted attacks or by advanced persistent threat actors once exploit code becomes available.

1. Apply the macOS Sequoia 15.4 update or later immediately to ensure the vulnerability is patched. 2. Restrict installation of applications to trusted sources such as the Mac App Store or verified developers to reduce the risk of malicious apps exploiting this flaw. 3. Employ application whitelisting and endpoint protection solutions capable of detecting unauthorized modifications to protected file system areas. 4. Educate users about the risks of installing untrusted software and the importance of avoiding suspicious links or files that require user interaction. 5. Monitor system logs and file integrity monitoring tools for unusual changes in system directories or binaries. 6. Implement least privilege principles to limit the ability of applications to influence environment variables or execute code with elevated permissions. 7. Consider using macOS security features such as System Integrity Protection (SIP) and notarization to further restrict unauthorized modifications. 8. Maintain regular backups of critical systems to enable recovery in case of compromise.