CVE-2025-43254 is a vulnerability identified in Apple macOS involving an out-of-bounds read condition caused by improper input validation when processing certain maliciously crafted files. This vulnerability is classified under CWE-125, which pertains to out-of-bounds read errors that can lead to memory corruption or application crashes. The flaw allows an attacker to cause unexpected termination of applications by tricking a user into opening a specially crafted file. The vulnerability affects multiple macOS versions prior to the patched releases: macOS Sequoia 15.6, Ventura 13.7.7, and Sonoma 14.7.7. The CVSS v3.1 score is 7.1, indicating high severity, with the vector AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H. This means the attack requires local access (local vector), low attack complexity, no privileges, but user interaction is necessary. The scope is unchanged, and the impact is high on confidentiality and availability but none on integrity. Although no exploits have been reported in the wild, the vulnerability could be leveraged to cause denial-of-service conditions or potentially leak sensitive information from memory due to the out-of-bounds read. The fix involves improved input validation to prevent the out-of-bounds read condition. This vulnerability is particularly relevant for environments where macOS is widely used, and users may open files from untrusted sources.

For European organizations, the primary impact of CVE-2025-43254 is the risk of denial-of-service through unexpected application crashes, which can disrupt business operations, especially in environments dependent on macOS applications. The high confidentiality impact suggests a potential for sensitive data exposure, which could lead to information leakage if exploited. Sectors such as finance, healthcare, government, and technology that utilize macOS devices for critical workflows may face operational and reputational risks. Additionally, the requirement for user interaction means phishing or social engineering campaigns could be used to deliver malicious files, increasing the threat surface. The absence of known exploits currently limits immediate risk, but the availability of a high-severity vulnerability necessitates proactive patching to prevent future exploitation. Organizations with remote or hybrid workforces using macOS devices are particularly vulnerable if endpoint security controls are insufficient.

1. Immediately apply the security updates macOS Sequoia 15.6, Ventura 13.7.7, or Sonoma 14.7.7 to all affected systems to remediate the vulnerability. 2. Implement strict controls on file sources, including disabling or restricting the opening of files from untrusted or unknown origins, especially in email attachments or downloads. 3. Deploy endpoint detection and response (EDR) solutions capable of monitoring for anomalous application crashes or suspicious file processing behaviors. 4. Educate users on the risks of opening unexpected or suspicious files and enforce policies for verifying file authenticity before opening. 5. Use application whitelisting to limit execution of unauthorized or unknown applications that might process malicious files. 6. Employ network segmentation to isolate macOS systems handling sensitive data, reducing lateral movement risk in case of exploitation. 7. Regularly audit and monitor macOS systems for signs of exploitation attempts or crashes related to file processing. 8. Coordinate with Apple support and security advisories to stay informed about any emerging exploits or additional patches.