CVE-2026-21975 is a vulnerability identified in the Java Virtual Machine (Java VM) component embedded within Oracle Database Server versions 19.3 to 19.29 and 21.3 to 21.20. The flaw allows an attacker with authenticated user privileges and network access via Oracle Net to exploit the vulnerability to compromise the Java VM. Specifically, the attacker can cause the Java VM to hang or crash repeatedly, resulting in a denial of service (DoS) condition. The attack requires user interaction from a third party, meaning that a victim must perform some action (such as clicking a link or opening a file) for the exploit to succeed. The vulnerability does not allow unauthorized access to data or modification of data, but it impacts availability by causing the Java VM to become unresponsive. The CVSS 3.1 vector (AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:N/A:H) indicates network attack vector, low attack complexity, high privileges required, user interaction required, unchanged scope, and impact limited to availability. No public exploits have been reported to date, but the vulnerability is considered easily exploitable under the specified conditions. The vulnerability affects Oracle Database Server installations that use the Java VM component, which is often leveraged for stored procedures, custom Java applications, or extensions within the database environment.

For European organizations, the primary impact of CVE-2026-21975 is the potential disruption of critical database services due to denial of service attacks targeting the Java VM within Oracle Database Server. This can lead to downtime of applications relying on the database, affecting business continuity, especially in sectors such as finance, telecommunications, government, and critical infrastructure where Oracle Database is widely deployed. Although the vulnerability does not expose sensitive data or allow data manipulation, the availability impact can cause operational delays, loss of productivity, and potential financial losses. Organizations with complex Oracle environments that integrate Java components are particularly at risk. The requirement for high privileges and user interaction somewhat limits the attack surface but does not eliminate the risk, especially in environments with many privileged users or where social engineering is feasible. Given the widespread use of Oracle Database in Europe, this vulnerability could affect a broad range of industries and public sector entities.

To mitigate CVE-2026-21975, European organizations should: 1) Apply Oracle's security patches or updates as soon as they become available for the affected Oracle Database versions. 2) Restrict network access to Oracle Net services to trusted hosts and networks only, using firewalls and network segmentation to limit exposure. 3) Enforce the principle of least privilege by limiting high privileged user accounts and monitoring their activity closely. 4) Educate users about social engineering risks to reduce the likelihood of successful user interaction required for exploitation. 5) Disable or remove unnecessary Java VM components or features within Oracle Database if not required for business processes. 6) Implement robust monitoring and alerting for unusual database or Java VM crashes to detect potential exploitation attempts early. 7) Regularly review and audit Oracle Database configurations and user privileges to ensure compliance with security best practices. These steps go beyond generic advice by focusing on reducing attack surface, controlling privileged access, and enhancing detection capabilities specific to this vulnerability.