CVE-2025-21494 is a vulnerability in Oracle MySQL Server's privilege management component that allows a high-privileged attacker with local access to the server infrastructure to cause a denial-of-service condition by hanging or crashing the MySQL Server process. The affected versions include MySQL Server 8.0.39 and earlier, 8.4.2 and earlier, and 9.0.1 and earlier. The vulnerability is classified under CWE-770, which relates to allocation of resources without limits or throttling, leading to potential resource exhaustion or deadlock scenarios. The attack vector requires local access (AV:L), high attack complexity (AC:H), and high privileges (PR:H), with no user interaction (UI:N). The impact is limited to availability (A:H), with no confidentiality or integrity compromise. The CVSS v3.1 base score is 4.1, indicating a medium severity primarily due to the difficulty of exploitation and limited scope. There are no known public exploits or patches at the time of publication. Successful exploitation results in repeated crashes or hangs, causing denial of service to applications relying on MySQL Server. This vulnerability highlights the importance of controlling privileged access and monitoring server stability.

For European organizations, the primary impact of CVE-2025-21494 is the potential for denial-of-service attacks against MySQL Server instances, which could disrupt critical business applications and services relying on database availability. Industries such as finance, telecommunications, healthcare, and e-commerce, which heavily depend on MySQL for data management, may experience operational downtime, leading to financial losses and reputational damage. Since exploitation requires high privileges and local access, the threat is more relevant to insider threats or attackers who have already compromised internal systems. The lack of confidentiality or integrity impact reduces the risk of data breaches but does not eliminate the operational risks associated with service outages. European data centers hosting MySQL infrastructure must consider this vulnerability in their risk assessments, especially where high availability is mandated by regulatory requirements such as GDPR.

1. Restrict and tightly control high-privileged access to MySQL Server infrastructure to trusted administrators only, employing the principle of least privilege. 2. Implement robust internal network segmentation and access controls to limit local access to MySQL hosts. 3. Monitor MySQL Server logs and system health metrics for signs of unusual crashes or hangs that could indicate exploitation attempts. 4. Prepare incident response plans to quickly recover MySQL services in case of denial-of-service events. 5. Stay informed on Oracle's security advisories and apply patches or updates promptly once available. 6. Consider deploying MySQL high-availability configurations (e.g., clustering, replication) to mitigate the impact of potential downtime. 7. Conduct regular security audits and penetration testing focusing on privilege escalation and local access controls to identify weaknesses before exploitation.