CVE-2022-26761 is a high-severity memory corruption vulnerability affecting Apple's macOS Catalina and Big Sur (specifically addressed in Security Update 2022-004 Catalina and macOS Big Sur 11.6.6). The vulnerability arises from improper memory handling that could allow a malicious application to execute arbitrary code with kernel-level privileges. This means an attacker who successfully exploits this flaw can gain the highest level of control over the affected system, bypassing typical user-level restrictions. The vulnerability is classified under CWE-787 (Out-of-bounds Write), indicating that the flaw involves writing data outside the intended memory boundaries, which can corrupt memory and lead to code execution. The CVSS v3.1 base score of 7.8 reflects a high-severity issue, with an attack vector requiring local access (AV:L), low attack complexity (AC:L), no privileges required (PR:N), but user interaction is necessary (UI:R). The impact on confidentiality, integrity, and availability is high, meaning that exploitation could lead to full system compromise, data theft, or denial of service. Although no known exploits are reported in the wild at the time of publication, the nature of the vulnerability and its kernel-level impact make it a critical concern for users of affected macOS versions. The fix involves improved memory handling implemented in the specified security updates, underscoring the importance of timely patching.

For European organizations, this vulnerability poses a significant risk, especially those relying on Apple macOS Catalina or Big Sur systems within their IT infrastructure. The ability for an application to escalate privileges to kernel level can lead to complete system compromise, enabling attackers to bypass security controls, access sensitive data, install persistent malware, or disrupt operations. Organizations in sectors such as finance, healthcare, government, and critical infrastructure are particularly vulnerable due to the sensitive nature of their data and the potential impact of operational disruption. Additionally, the requirement for local access and user interaction means that phishing or social engineering could be vectors for exploitation, increasing the risk in environments where users may inadvertently run malicious applications. The high confidentiality, integrity, and availability impact could result in data breaches, intellectual property theft, regulatory non-compliance (e.g., GDPR), and reputational damage. Given the widespread use of Apple devices in European enterprises and public sector organizations, the threat is material and demands immediate attention.

European organizations should prioritize the deployment of Apple's Security Update 2022-004 Catalina and macOS Big Sur 11.6.6 to remediate this vulnerability. Beyond patching, organizations should implement strict application whitelisting to prevent unauthorized or untrusted applications from executing, reducing the risk of local exploitation. Endpoint detection and response (EDR) solutions should be configured to monitor for suspicious behaviors indicative of privilege escalation or kernel-level attacks. User awareness training is essential to minimize the risk of social engineering or phishing attacks that could deliver malicious applications requiring user interaction. Additionally, enforcing the principle of least privilege on user accounts and restricting local administrative rights can limit the potential for exploitation. Regular auditing of installed applications and system logs can help detect early signs of compromise. Network segmentation and strong access controls should be employed to limit lateral movement if a device is compromised. Finally, organizations should maintain an up-to-date inventory of Apple devices to ensure all vulnerable systems are identified and patched promptly.