CVE-2025-36428 is a vulnerability identified in IBM Db2 for Linux, UNIX, and Windows, specifically affecting versions 11.5.0 through 11.5.9 and 12.1.0 through 12.1.3. The vulnerability stems from CWE-1284, which involves improper validation of specified quantity in input. When the RPSCAN feature is enabled, an authenticated user can exploit this flaw by submitting specially crafted queries that contain improperly neutralized special elements. This leads to a denial of service condition, effectively disrupting the availability of the database service. The vulnerability does not affect confidentiality or integrity but solely impacts availability. The attack vector is network-based (AV:N), requires low privileges (PR:L), does not require user interaction (UI:N), and affects an unchanged scope (S:U). The CVSS v3.1 base score is 5.3, indicating medium severity. No public exploits are known at this time, but the vulnerability could be leveraged by insiders or attackers with valid credentials to disrupt critical database operations. The lack of patches at the time of reporting necessitates immediate mitigation through configuration changes such as disabling RPSCAN if it is not essential. IBM Db2 is widely used in enterprise environments for critical data management, making this vulnerability a concern for organizations relying on these versions and configurations.

The primary impact of CVE-2025-36428 is denial of service, which can cause significant disruption to business operations relying on IBM Db2 databases. For European organizations, this could mean downtime in critical applications such as financial services, healthcare, manufacturing, and government systems that depend on Db2 for data storage and processing. The disruption could lead to operational delays, loss of productivity, and potential financial losses. Since the vulnerability requires authentication, the risk is higher from insider threats or compromised accounts. The availability impact could also affect service level agreements (SLAs) and damage organizational reputation. Given the widespread use of IBM Db2 in Europe, particularly in large enterprises and public sector institutions, the threat could have broad implications if exploited. However, the absence of known exploits and the medium severity rating suggest the risk is moderate but should not be ignored.

1. Immediately review and assess whether the RPSCAN feature is enabled on IBM Db2 instances; if it is not essential, disable it to eliminate the attack vector. 2. Monitor database access logs for unusual query patterns or repeated failures that could indicate exploitation attempts. 3. Enforce strict access controls and multi-factor authentication to reduce the risk of credential compromise. 4. Apply the latest IBM Db2 patches and updates as soon as they become available to address this vulnerability directly. 5. Conduct regular security audits and vulnerability assessments focusing on database configurations and user privileges. 6. Implement network segmentation and firewall rules to limit access to Db2 servers only to trusted hosts and users. 7. Educate database administrators and security teams about this vulnerability and the importance of monitoring RPSCAN usage. 8. Prepare incident response plans to quickly address potential denial of service events impacting database availability.