CVE-2025-21580 is a vulnerability identified in Oracle Corporation's MySQL Server affecting 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 resides in the Server: DML component and allows an attacker with high privileges and network access via multiple protocols to cause the MySQL Server to hang or crash repeatedly, resulting in a denial-of-service (DoS) condition. The vulnerability does not impact confidentiality or integrity but solely affects availability. The CVSS 3.1 base score is 4.9, with vector AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H, indicating network attack vector, low attack complexity, required high privileges, no user interaction, unchanged scope, and impact limited to availability. The CWE associated is CWE-732, which relates to incorrect permission assignment or management. No known exploits have been reported in the wild, and no official patches have been linked at the time of publication. The vulnerability is easily exploitable by a high-privileged attacker, which could be an insider or a compromised account with network access. The attack can be conducted over multiple protocols supported by MySQL, increasing the attack surface. The consequence is a complete denial of service, which can disrupt business operations relying on MySQL databases. This vulnerability underscores the importance of strict privilege management and network access controls for database servers.

For European organizations, this vulnerability poses a risk primarily to the availability of critical database services running MySQL Server in the affected versions. Industries such as finance, healthcare, telecommunications, and government services that rely heavily on MySQL for backend data storage could experience service outages, leading to operational disruptions and potential financial losses. Although the vulnerability does not allow data theft or modification, the denial-of-service condition could impact business continuity and service level agreements. Organizations with multi-tenant environments or cloud-hosted MySQL instances may face cascading effects if the database becomes unresponsive. Additionally, high-privileged attackers exploiting this flaw could leverage the DoS as a diversion for other malicious activities. The lack of known exploits currently reduces immediate risk, but the ease of exploitation and network accessibility mean that once exploits emerge, rapid impact is possible. European entities with stringent uptime requirements and regulatory obligations around service availability must prioritize mitigation to avoid compliance issues and reputational damage.

1. Restrict network access to MySQL servers by implementing strict firewall rules and network segmentation, allowing only trusted hosts and applications to communicate with the database. 2. Enforce the principle of least privilege by auditing and limiting high-privileged accounts that have network access to MySQL, including administrative and service accounts. 3. Monitor MySQL server logs and network traffic for unusual patterns indicative of repeated crashes or hangs, enabling early detection of exploitation attempts. 4. Deploy intrusion detection/prevention systems (IDS/IPS) tuned to detect anomalous MySQL protocol activity or repeated connection attempts that could trigger the vulnerability. 5. Prepare for patch deployment by tracking Oracle’s security advisories and testing updates in controlled environments to ensure compatibility and stability. 6. Consider implementing high-availability and failover mechanisms for MySQL to minimize service disruption in case of an attack. 7. Conduct regular security assessments and penetration testing focusing on privilege escalation and network access controls around MySQL infrastructure. 8. Educate database administrators and security teams about the vulnerability specifics and response procedures to ensure rapid incident handling.