CVE-2024-21413 is a critical remote code execution vulnerability identified in Microsoft Outlook, part of Microsoft Office 2019 version 19.0.0. The root cause is improper input validation (CWE-20), which allows an attacker to craft malicious input that Outlook processes unsafely. This vulnerability can be exploited remotely over the network without requiring any authentication or user interaction, making it highly dangerous. Successful exploitation enables an attacker to execute arbitrary code with the privileges of the targeted user, potentially leading to full system compromise. The CVSS v3.1 score of 9.8 reflects the vulnerability's critical nature, with network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N). The impact affects confidentiality, integrity, and availability (all rated high). Although no known exploits have been reported in the wild yet, the vulnerability's characteristics make it a prime candidate for future exploitation. The vulnerability was reserved in December 2023 and published in February 2024, with Microsoft expected to release patches. Until patches are applied, systems remain at high risk. This vulnerability specifically affects Microsoft Office 2019 version 19.0.0, widely used in enterprise environments worldwide.

The impact on European organizations is significant due to the widespread use of Microsoft Office 2019, particularly Outlook, in business and government sectors. Exploitation could lead to unauthorized remote code execution, allowing attackers to gain control over affected systems, steal sensitive data, disrupt operations, or deploy ransomware. Confidentiality breaches could expose personal and corporate data, violating GDPR and other data protection regulations, potentially resulting in legal and financial penalties. Integrity and availability impacts could disrupt critical business processes, causing operational downtime and reputational damage. The lack of required authentication and user interaction increases the likelihood of successful attacks, especially via phishing or malicious email campaigns. Organizations with large numbers of Outlook users, especially in sectors such as finance, healthcare, and public administration, face elevated risks. The threat also increases the attack surface for advanced persistent threat (APT) groups targeting European entities.

Organizations should prioritize the deployment of official security patches from Microsoft as soon as they become available to remediate CVE-2024-21413. Until patches are applied, implement enhanced email filtering to block suspicious attachments and links, and deploy advanced threat protection solutions capable of detecting malicious payloads targeting Outlook. Network segmentation should be used to isolate critical systems and limit lateral movement in case of compromise. Employ strict access controls and monitor logs for unusual activity related to Outlook processes. User awareness training should emphasize caution with unexpected emails and attachments. Consider disabling or restricting legacy protocols and features in Outlook that may increase exposure. Regularly update and audit endpoint protection tools to detect exploitation attempts. Organizations should also prepare incident response plans specific to email-based remote code execution attacks to minimize impact if exploitation occurs.