CVE-2025-30682 is a vulnerability identified in Oracle MySQL Server's Optimizer component affecting multiple supported versions: 8.0.0 through 8.0.41, 8.4.0 through 8.4.4, and 9.0.0 through 9.2.0. The flaw allows an attacker with low privileges and network access to exploit the server via multiple protocols to cause a hang or repeated crashes, resulting in a complete denial-of-service (DoS) condition. The vulnerability has a CVSS 3.1 base score of 6.5, indicating a medium severity primarily due to its impact on availability (A:H), with no impact on confidentiality or integrity. The attack vector is network-based (AV:N), requires low attack complexity (AC:L), and low privileges (PR:L), with no user interaction (UI:N). The vulnerability is classified under CWE-732, which relates to incorrect permission assignment or management, suggesting that the server's access control or privilege separation mechanisms are insufficiently restrictive. No known exploits have been reported in the wild, and no official patches have been linked at the time of publication. The vulnerability's exploitation could disrupt database services, affecting applications and services dependent on MySQL Server, potentially causing operational downtime and service degradation.

For European organizations, the primary impact of CVE-2025-30682 is the potential for denial-of-service attacks against MySQL Server instances, which are widely used in enterprise environments for critical data storage and application backends. Such disruptions can lead to significant operational downtime, loss of service availability, and cascading effects on business processes reliant on database availability. Sectors such as finance, healthcare, e-commerce, and public administration, which heavily depend on database uptime, could experience service interruptions, impacting customer trust and regulatory compliance. Additionally, repeated crashes may increase the risk of data corruption or loss if recovery mechanisms are inadequate. The medium severity rating reflects the absence of direct data compromise but highlights the risk to service continuity. European organizations with exposed MySQL servers accessible over the network, especially those with low privilege access paths, are at heightened risk. The lack of known exploits currently provides a window for proactive mitigation, but the ease of exploitation underscores the urgency of addressing this vulnerability.

1. Immediately audit and restrict network access to MySQL Server instances, ensuring only trusted hosts and applications can connect, preferably via VPNs or secure tunnels. 2. Implement strict access controls and least privilege principles for MySQL user accounts, minimizing the number of low-privileged accounts with network access. 3. Monitor MySQL server logs and system metrics for unusual patterns such as frequent crashes, hangs, or restarts that may indicate exploitation attempts. 4. Employ network-level intrusion detection/prevention systems (IDS/IPS) to detect anomalous traffic targeting MySQL protocols. 5. Prepare for rapid deployment of official patches from Oracle once released; subscribe to Oracle security advisories for timely updates. 6. Consider deploying MySQL server instances behind application firewalls or proxy layers that can filter and limit protocol usage. 7. Regularly back up databases and test recovery procedures to mitigate potential data loss from service disruptions. 8. Conduct internal penetration testing to verify the effectiveness of mitigations and identify any residual exposure. 9. For cloud deployments, leverage provider-specific security groups and network ACLs to tightly control access to MySQL endpoints. 10. Educate system administrators and security teams about this vulnerability and ensure incident response plans include scenarios for MySQL DoS attacks.