CVE-2025-30685 is a vulnerability in the replication component of Oracle MySQL Server affecting multiple major 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 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 does not impact confidentiality or integrity but solely affects availability. The CVSS 3.1 base score is 4.9, reflecting a medium severity level, with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), required privileges are high (PR:H), no user interaction (UI:N), unchanged scope (S:U), and impact limited to availability (A:H). The underlying weakness is classified under CWE-732, which relates to incorrect permission assignment or management. No known exploits have been reported in the wild, and no official patches were linked at the time of disclosure. The vulnerability is easily exploitable by attackers who already have high-level network access, making it critical for environments where MySQL Server is exposed or accessible by privileged users over the network. The replication component's involvement suggests that distributed or clustered MySQL deployments could be particularly vulnerable to service disruption.

For European organizations, this vulnerability poses a risk primarily to the availability of MySQL Server instances, which are widely used in enterprise environments for critical applications and data storage. A successful exploitation could lead to service outages, impacting business continuity, customer-facing applications, and internal operations dependent on database availability. Industries such as finance, telecommunications, healthcare, and public sector entities that rely heavily on MySQL for transactional or replicated data services could face operational disruptions. Although the vulnerability does not allow data theft or modification, the denial of service could indirectly affect data integrity if failover or recovery mechanisms are not robust. Additionally, organizations with compliance obligations around uptime and service availability (e.g., financial institutions under PSD2 or healthcare providers under GDPR mandates) may face regulatory scrutiny if service disruptions occur. The requirement for high privileges limits the attack surface but also means insider threats or compromised privileged accounts could exploit this vulnerability.

European organizations should implement strict network segmentation and access controls to limit high privileged network access to MySQL Servers, especially restricting replication protocol access to trusted hosts only. Employing strong authentication and monitoring for anomalous privileged user activity can reduce the risk of exploitation. Organizations should maintain up-to-date inventory of MySQL Server versions in use and prepare to apply vendor patches promptly once released. In the interim, consider disabling or restricting replication features if not essential, or deploying rate limiting and connection filtering to mitigate potential attack vectors. Implement robust monitoring and alerting for MySQL server crashes or hangs to enable rapid incident response. Backup and disaster recovery plans should be tested to ensure quick restoration of services in case of denial of service. Finally, review and harden MySQL Server configurations to minimize exposure of replication services over untrusted networks.