CVE-2026-105466 in Db2
Summary
by MITRE • 10/12/2026
IBM Db2 11.5.0 through 11.5.9, and 12.1.0 through 12.1.5 is vulnerable to a denial of service when inserting into a table with XML columns under specific conditions.
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Analysis
by VulDB Data Team • 10/12/2026
The vulnerability identified in IBM Db2 versions 11.5.0 through 11.5.9 and 12.1.0 through 12.1.5 represents a critical reliability issue within the database management system's handling of Extensible Markup Language data types. This flaw specifically manifests during insert operations targeting tables that contain XML columns, indicating a weakness in how the engine processes or validates structured text data before committing it to storage. The existence of this vulnerability highlights potential gaps in input validation and resource allocation mechanisms when dealing with complex hierarchical data structures within relational database environments.
At its core, this is a denial of service condition triggered by specific insertion scenarios involving XML payloads. When an application attempts to insert data into the affected table structure under particular conditions that are not fully detailed but likely involve malformed or excessively large XML documents, the Db2 engine fails to handle the operation gracefully. Instead of returning an appropriate error code or rejecting the invalid input, the database process encounters a fatal exception or enters an unrecoverable state. This results in the termination of the database instance or the specific connection handling the request, thereby rendering the service unavailable for subsequent operations until manual intervention is performed by system administrators to restart the affected components.
The operational impact of this vulnerability extends beyond simple downtime. For organizations relying on IBM Db2 for mission-critical applications, such as financial services, healthcare systems, or enterprise resource planning platforms, an unexpected database crash can lead to significant data loss if transactions were in progress and not properly committed prior to the failure. Furthermore, the need for manual restarts introduces latency that disrupts business continuity and user experience. Attackers who have gained access to the database interface, whether through compromised credentials or network exposure, could exploit this flaw as part of a broader attack strategy to degrade service availability without necessarily stealing sensitive data, aligning with tactics aimed at disrupting operational integrity rather than confidentiality.
From a classification perspective, this vulnerability is categorized under CWE-400: Uncontrolled Resource Consumption and potentially CWE-20: Improper Input Validation if the root cause involves insufficient checking of XML structure or size before processing. In terms of offensive security frameworks, it aligns with MITRE ATT&CK technique T1499: Endpoint Denial of Service, specifically where an attacker leverages application-level vulnerabilities to exhaust system resources or crash services. The specific context of database manipulation also touches upon aspects of data integrity and availability assurance which are central pillars of information security management systems such as ISO/IEC 27001.
Mitigation strategies for this vulnerability primarily involve applying the latest service updates provided by IBM, which contain patches designed to improve input validation logic and error handling routines within the XML processing engine. Organizations should ensure that their Db2 instances are updated to versions beyond 11.5.9 and 12.1.5 where these flaws have been addressed. In addition to patching, implementing robust application-layer controls is recommended. This includes validating XML schemas strictly before data reaches the database layer, enforcing size limits on incoming payloads, and utilizing parameterized queries or prepared statements that can better isolate input from execution logic. Network-level protections such as Web Application Firewalls may also help filter out suspiciously large or malformed requests before they reach the vulnerable application components interacting with Db2.