CVE-2024-21173 is a vulnerability in Oracle MySQL Server's InnoDB component affecting versions 8.0.37 and earlier, as well as 8.4.0 and earlier. The flaw allows an attacker with high privileges and network access to exploit multiple protocols to cause the MySQL Server to hang or crash repeatedly, resulting in a complete denial of service (DoS). The vulnerability is classified under CWE-400, indicating a resource exhaustion or DoS condition. The CVSS 3.1 base score is 4.9, reflecting a medium severity level primarily due to its impact on availability only, with no confidentiality or integrity compromise. The attack vector is network-based (AV:N), with low attack complexity (AC:L), requiring high privileges (PR:H), and no user interaction (UI:N). The scope remains unchanged (S:U), meaning the impact is limited to the vulnerable component. No known exploits are currently reported in the wild, and no official patches have been linked yet. The vulnerability could be triggered via multiple network protocols supported by MySQL Server, emphasizing the need for careful access control. The lack of confidentiality or integrity impact means data leakage or unauthorized data modification is not a concern here, but the availability of critical database services can be severely disrupted, potentially affecting dependent applications and services.

For European organizations, the primary impact of CVE-2024-21173 is the potential for denial of service against MySQL Server instances, which could disrupt business-critical applications relying on these databases. Industries such as finance, healthcare, telecommunications, and public sector entities that depend heavily on MySQL for backend data storage could experience service outages, leading to operational downtime, loss of productivity, and potential regulatory compliance issues related to service availability. Although the vulnerability does not allow data theft or corruption, the inability to access database services can indirectly affect data integrity and business continuity. Organizations with distributed MySQL deployments or those exposed to network access by high privileged users are at greater risk. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits once the vulnerability details are widely known. The impact is more pronounced in environments where MySQL servers are internet-facing or accessible over less secure networks without strict access controls.

1. Restrict network access to MySQL Server instances, especially limiting high privileged user access to trusted internal networks only. 2. Implement strict firewall rules and network segmentation to minimize exposure of MySQL services to untrusted networks. 3. Monitor MySQL server logs and system metrics for signs of hangs, crashes, or unusual resource consumption that could indicate exploitation attempts. 4. Apply the principle of least privilege to MySQL user accounts, ensuring that high privilege accounts are used sparingly and only when necessary. 5. Stay alert for official patches or updates from Oracle and apply them promptly once available. 6. Consider deploying failover or high availability configurations to mitigate the impact of potential DoS conditions. 7. Conduct regular vulnerability assessments and penetration testing focused on database services to identify and remediate exposure. 8. Use network intrusion detection/prevention systems (IDS/IPS) to detect anomalous traffic patterns targeting MySQL protocols. 9. Educate database administrators and security teams about this vulnerability and encourage proactive monitoring and incident response readiness.