CVE-2025-30689 is a vulnerability identified in the Oracle MySQL Server product, specifically within the Server Optimizer component. It affects multiple supported versions, including 8.0.0 to 8.0.41, 8.4.0 to 8.4.4, and 9.0.0 to 9.2.0. The flaw allows an attacker with high privileges and network access through multiple protocols to cause the MySQL Server to hang or crash repeatedly, resulting in a complete denial-of-service (DoS). The vulnerability does not compromise data confidentiality or integrity but impacts availability by causing service outages. The CVSS 3.1 base score is 4.9, reflecting medium severity, with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), requiring high privileges (PR:H), no user interaction (UI:N), unchanged scope (S:U), and impact limited to availability (A:H). No public exploits have been reported, and no patches are currently linked, though Oracle is expected to release updates. The vulnerability is categorized under CWE-284 (Improper Access Control), indicating that insufficient access control mechanisms allow the attacker to trigger the DoS condition. The attack surface includes any network-accessible MySQL Server instances where an attacker has elevated privileges, which could be through compromised credentials or insider threats. The multiple protocol access vector suggests that various MySQL communication protocols could be leveraged for exploitation. This vulnerability primarily threatens service availability, potentially disrupting applications and services dependent on MySQL databases.

For European organizations, this vulnerability poses a risk of service disruption due to denial-of-service attacks on MySQL Server instances. Organizations relying heavily on MySQL for critical business applications, financial services, healthcare data management, or public sector services could face operational downtime, impacting business continuity and service delivery. Although the vulnerability does not allow data theft or modification, the loss of availability can lead to significant indirect consequences such as loss of customer trust, regulatory scrutiny, and financial losses. The requirement for high privileges limits the threat to scenarios where attackers have already gained elevated access, such as through credential compromise or insider threats. However, once exploited, the attacker can repeatedly crash the database server, causing persistent outages. European entities with complex network environments and multiple MySQL instances may face challenges in quickly identifying and mitigating the issue. The absence of known exploits in the wild currently reduces immediate risk, but the potential for future exploitation remains, especially if attackers develop automated tools. The impact is more pronounced in sectors with stringent uptime requirements and where MySQL is a core component of IT infrastructure.

1. Restrict network access to MySQL Server instances to trusted hosts and networks only, using firewalls and network segmentation to limit exposure. 2. Enforce strict access controls and monitor for unauthorized privilege escalations to prevent attackers from obtaining high-privileged accounts. 3. Implement robust credential management, including multi-factor authentication and regular password audits, to reduce the risk of credential compromise. 4. Monitor MySQL Server logs and system behavior for signs of unusual activity or repeated crashes that may indicate exploitation attempts. 5. Prepare incident response plans specifically addressing MySQL service outages to minimize downtime and recovery time. 6. Stay informed on Oracle security advisories and apply patches promptly once they become available to remediate the vulnerability. 7. Consider deploying MySQL high availability and failover solutions to mitigate the impact of potential DoS conditions. 8. Conduct regular vulnerability assessments and penetration testing focusing on database servers to identify and remediate privilege escalation risks. 9. Limit the use of high-privileged accounts for routine operations and adopt the principle of least privilege wherever possible. 10. Use network intrusion detection/prevention systems (IDS/IPS) to detect and block suspicious traffic targeting MySQL protocols.