CVE-2026-17463 in Db2
Summary
by MITRE • 09/14/2026
IBM Db2 11.5.0 through 11.5.9, and 12.1.0 through 12.1.5 for Linux, UNIX and Windows (includes DB2 Connect Server) could allow a remote authenticated attacker to cause a denial of service due to uncontrolled resource consumption.
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Analysis
by VulDB Data Team • 09/14/2026
The vulnerability identified in IBM Db2 versions 11.5.0 through 11.5.9 and 12.1.0 through 12.1.5 for Linux, UNIX, Windows, including the DB2 Connect Server component, represents a significant risk to database availability due to uncontrolled resource consumption triggered by remote authenticated attackers. This flaw is categorized under CWE-400, which describes conditions where an application does not properly control the allocation and maintenance of system resources, leading to exhaustion that can degrade performance or cause crashes. The core technical issue lies in the handling of specific requests processed by the database engine, where insufficient validation or rate limiting allows a malicious actor to consume excessive CPU cycles, memory, or I/O bandwidth without proportional limits being enforced within the application logic.
From an operational perspective, this vulnerability enables a denial-of-service scenario that can severely impact business continuity for organizations relying on IBM Db2 for critical data operations. Because the attack requires authentication, it targets users who have legitimate access credentials but possess malicious intent or whose accounts may be compromised by external threat actors. Once exploited, the attacker can submit crafted queries or connection patterns that force the database server to allocate disproportionate resources, potentially leading to system instability, service interruptions, and inability for other authorized users to connect or execute valid transactions. This type of attack is particularly dangerous in multi-tenant environments where resource isolation between different user groups may be insufficiently enforced at the application layer rather than just the infrastructure level.
The exploitation vector aligns with ATT&CK technique T1499, Endpoint Denial of Service, specifically reflecting methods that target system resources to make them unavailable to intended users. In the context of database management systems, this often manifests as query-based resource exhaustion where complex or malformed SQL statements are executed repeatedly or in a manner designed to trigger inefficient execution plans within the optimizer. The presence of DB2 Connect Server extends the attack surface by allowing connections from remote clients over network protocols, thereby facilitating remote exploitation without requiring physical access to the host machine. This expands the potential impact beyond local users to include any authenticated user with network connectivity to the affected service endpoints.
Mitigation strategies must focus on both immediate remediation and long-term architectural hardening. The primary defense is applying the vendor-provided security patches that address the specific code paths responsible for uncontrolled resource consumption, ensuring all instances of IBM Db2 within the specified version ranges are updated to their latest secure releases. Beyond patching, organizations should implement strict access control policies using role-based access control principles to limit which authenticated users can execute high-resource queries or administrative functions. Network-level controls such as rate limiting on database ports and intrusion detection systems configured to identify patterns of resource-intensive query execution can also serve as effective compensating controls to detect and block potential exploitation attempts before they cause significant service degradation.