CVE-2026-104332 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 executing a specially crafted query with a Materialized Query Table
Be aware that VulDB is the high quality source for vulnerability data.
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 denial of service risk associated with the database engine's handling of Materialized Query Tables, also known as summary tables or query result caches. These structures are designed to precompute and store the results of complex queries to improve performance for subsequent read operations. The flaw lies in the specific processing logic that validates and executes queries against these cached data structures when they involve specially crafted input parameters. An attacker who possesses valid credentials with sufficient privileges to execute such queries can trigger this vulnerability, leading to a catastrophic failure within the database management system's process stack.
From a technical perspective, the core issue stems from improper validation or resource management during the execution phase of a query targeting a Materialized Query Table. When the database engine attempts to resolve the query against the precomputed data, it encounters an unexpected state or memory condition that causes the service to become unresponsive or crash entirely. This is not merely a logical error but a stability failure where the application fails to handle edge cases in query parsing or execution plans involving these specific table types. The lack of robust exception handling allows this malformed request to propagate through critical system layers, resulting in an immediate halt of database operations for all connected users and applications relying on that instance.
The operational impact of this vulnerability is severe due to the central role IBM Db2 plays in many enterprise environments. A successful exploitation results in a complete denial of service, meaning legitimate users are unable to access data or perform transactions during the outage period. This disruption can lead to significant business downtime, loss of productivity, and potential financial losses depending on the criticality of the affected systems. Furthermore, if the database instance is configured for high availability with automatic restarts, repeated exploitation attempts could cause a denial-of-service loop that consumes system resources such as CPU and memory during recovery cycles, exacerbating the impact even after the initial crash has been addressed by automated failover mechanisms.
This vulnerability aligns with CWE-400, which describes Uncontrolled Resource Consumption, specifically where an attacker can exhaust available resources or cause a service to stop responding due to improper handling of input that triggers excessive processing or memory allocation failures. In terms of offensive security frameworks, this falls under the MITRE ATT&CK technique T1498, Network Denial of Service, as it involves actions intended to impair the availability of networked services by exploiting software vulnerabilities rather than overwhelming bandwidth with traffic volume. It is also relevant to CWE-20, Improper Input Validation, since the root cause is likely a failure to adequately sanitize or validate the structure and parameters of the SQL query before execution against sensitive internal structures like Materialized Query Tables.
Mitigation strategies must prioritize immediate patching as recommended by IBM Security Advisories for these specific versions. Organizations should apply the latest cumulative fixes that address this denial of service flaw in Db2 11.5.x and 12.1.x releases. Until patches are applied, administrators can implement defensive measures such as restricting database access to only trusted IP addresses and enforcing strict role-based access control to ensure that only authorized personnel with a legitimate business need can execute complex queries against Materialized Query Tables. Additionally, deploying Web Application Firewalls or Database Activity Monitoring tools may help detect anomalous query patterns indicative of exploitation attempts, although the primary defense remains keeping the database software up to date with vendor-provided security updates.