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 issue arises from improper validation of specified quantities in input when the RPSCAN feature is enabled. RPSCAN is a Db2 feature that optimizes query processing by scanning result sets, but improper neutralization of special elements in the data query logic can be exploited by an authenticated user to trigger a denial of service condition. This vulnerability is classified under CWE-1284, which relates to improper validation of specified quantities in input, leading to unexpected behavior. The CVSS v3.1 score is 5.3 (medium), with an attack vector of network (remote), requiring low privileges and no user interaction, but with high attack complexity. The impact is limited to availability, as the vulnerability does not affect confidentiality or integrity. No public exploits have been reported yet, but the vulnerability could be leveraged to disrupt database services, causing downtime or degraded performance. The vulnerability was published on January 30, 2026, and IBM has not yet released patches, though monitoring IBM advisories is recommended. Organizations relying on Db2 with RPSCAN enabled should be aware of this risk and prepare mitigation strategies.

For European organizations, the primary impact of CVE-2025-36428 is the potential denial of service on critical database infrastructure running IBM Db2. This can lead to significant operational disruptions, especially in sectors reliant on continuous data availability such as finance, telecommunications, healthcare, and government services. Downtime or degraded performance of Db2 databases can interrupt transaction processing, data analytics, and application functionality, potentially causing financial losses and reputational damage. Since the vulnerability requires authentication, insider threats or compromised credentials could be leveraged to exploit this flaw. The absence of confidentiality or integrity impact reduces the risk of data breaches but does not diminish the operational risk. Organizations with high availability requirements and strict service level agreements (SLAs) may face compliance challenges if service disruptions occur. The medium severity rating suggests that while the threat is not critical, it warrants timely attention to avoid service interruptions.

1. Disable the RPSCAN feature if it is not essential for your database operations, as this directly mitigates the vulnerability vector. 2. Monitor IBM’s security advisories closely and apply official patches or updates as soon as they become available. 3. Implement strict access controls and multi-factor authentication to reduce the risk of unauthorized authenticated access. 4. Audit and monitor database query logs for unusual patterns or repeated queries that could indicate exploitation attempts targeting RPSCAN. 5. Conduct regular vulnerability assessments and penetration testing focused on database features and input validation mechanisms. 6. Establish robust incident response procedures to quickly identify and mitigate denial of service conditions affecting Db2. 7. Consider network segmentation and firewall rules to limit access to Db2 servers only to trusted hosts and users. 8. Educate database administrators and security teams about this vulnerability and the importance of secure configuration management.