CVE-2025-36136 is a resource allocation vulnerability classified under CWE-770, affecting IBM Db2 database server versions 11.5.0 through 11.5.9 and 12.1.0 through 12.1.3 across Linux, UNIX, and Windows platforms, including DB2 Connect Server. The issue arises from the database monitor script's incorrect detection logic, which under specific conditions mistakenly assumes the database instance is still starting. This misdetection leads to uncontrolled allocation of resources without proper limits or throttling, allowing a local user to trigger a denial of service by exhausting system resources. The vulnerability requires local access, has high attack complexity, and does not require user interaction or authentication privileges. While it does not compromise data confidentiality or integrity, the availability of the database service can be severely impacted, potentially disrupting business-critical operations. No public exploits have been reported yet, but the flaw's nature suggests that attackers with local access could leverage it to degrade or halt database services. IBM has published the vulnerability with a CVSS v3.1 score of 5.1, reflecting medium severity. The absence of patches at the time of reporting means organizations must monitor IBM advisories closely and prepare to apply fixes promptly. This vulnerability highlights the importance of resource management and monitoring in database environments to prevent denial of service conditions caused by flawed internal scripts.

For European organizations, the primary impact of CVE-2025-36136 is the potential denial of service on IBM Db2 database servers, which can disrupt critical business applications and services relying on these databases. Sectors such as finance, telecommunications, manufacturing, and government agencies that use IBM Db2 extensively may face operational downtime, leading to financial losses and service interruptions. The requirement for local access limits the attack surface to insiders or attackers who have already compromised a system within the network, but the high impact on availability can still cause significant disruption. Additionally, organizations with strict uptime and service level agreements (SLAs) may suffer reputational damage and regulatory scrutiny if database availability is compromised. The vulnerability does not expose data to theft or modification, but the loss of availability can indirectly affect business continuity and incident response capabilities. European entities with complex IT environments and legacy Db2 deployments should assess their exposure and readiness to respond to such resource exhaustion attacks.

To mitigate CVE-2025-36136, European organizations should: 1) Monitor IBM security advisories closely and apply patches or updates as soon as IBM releases them for affected Db2 versions. 2) Restrict local access to Db2 servers strictly, employing strong access controls and monitoring to prevent unauthorized local user activity. 3) Implement resource usage monitoring and alerting on Db2 instances to detect abnormal resource consumption patterns indicative of exploitation attempts. 4) Use system-level resource limits (e.g., cgroups on Linux) to constrain the maximum resources any single process or user can consume, reducing the risk of resource exhaustion. 5) Conduct regular audits of database monitor scripts and configurations to ensure they operate correctly and do not misinterpret instance states. 6) Consider upgrading to later Db2 versions not affected by this vulnerability if feasible. 7) Employ network segmentation and host-based intrusion detection to limit lateral movement and local access by potential attackers. These steps go beyond generic advice by focusing on controlling local access, monitoring resource usage, and preparing for rapid patch deployment.