CVE-2026-18166 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 for Linux, UNIX and Windows (includes DB2 Connect Server) could allow a remote authenticated attacker to obtain sensitive information due to improper authorization when using the CREATE WRAPPER command.
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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, as well as version 12.1.0 through 12.1.5 for Linux, UNIX, and Windows environments including the DB2 Connect Server component, represents a critical flaw in access control mechanisms governing database wrapper creation operations. This security issue specifically impacts authenticated users who possess specific privileges to execute administrative commands within the database environment. The core of the vulnerability lies in an improper authorization check associated with the CREATE WRAPPER command, which is used to define external data sources that allow Db2 to interact with non-relational or remote databases and services. When a user issues this command, the system fails to adequately verify whether the requesting entity has sufficient permissions not only to create the wrapper definition but also to access the underlying sensitive information associated with those external connections.
From a technical perspective, database wrappers serve as intermediaries that translate queries from Db2 into formats understandable by external data sources such as Hadoop, MongoDB, or other relational databases via JDBC or ODBC drivers. These wrappers often contain connection strings, authentication credentials, and configuration parameters necessary to establish these links. The flaw arises because the authorization logic does not strictly enforce separation of duties or least privilege principles during the instantiation of these wrapper objects. Consequently, an attacker who has gained authenticated access with relatively low-level privileges may be able to create a wrapper that points to sensitive internal resources or exploits misconfigured external connections to exfiltrate data that should remain restricted to higher-privileged administrators. This bypasses expected security boundaries because the system treats the creation of the wrapper as a valid administrative action without sufficiently validating the scope of access granted by that specific command context.
The operational impact of this vulnerability is significant, primarily centering on unauthorized information disclosure and potential lateral movement within an enterprise infrastructure. An attacker leveraging this flaw can retrieve sensitive data such as database connection strings, user credentials stored in wrapper definitions, or metadata from external systems linked via these wrappers. This exposure facilitates further attacks by providing the adversary with valuable intelligence about the network topology, authentication mechanisms, and other databases that may be interconnected through Db2. In environments where DB2 Connect Server is deployed to facilitate cross-platform database access, this vulnerability could allow an attacker to pivot between different database platforms or extract data from systems that are not directly exposed to the internet but rely on Db2 as a gateway. The ability to read sensitive information undermines the confidentiality guarantees provided by the database management system and can lead to compliance violations regarding data protection regulations such as GDPR, HIPAA, or PCI-DSS depending on the nature of the exposed data.
This vulnerability aligns with CWE-862, which describes Missing Authorization, indicating that a software product does not perform an authorization check when an actor attempts to access a resource or perform an action. Furthermore, in terms of tactical classification under the MITRE ATT&CK framework, this flaw supports techniques related to Credential Access and Data from Information Repositories. Specifically, it enables adversaries to gather credentials stored within wrapper configurations or extract data directly from linked external repositories without triggering standard alerting mechanisms associated with privilege escalation attempts. The lack of strict authorization checks allows for stealthy reconnaissance and data staging activities that are difficult to detect using traditional perimeter-based security controls alone.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. IBM has released patches addressing this issue in subsequent maintenance levels, so applying the latest service updates is the primary corrective action. Organizations should ensure their Db2 instances are updated beyond version 11.5.9 for the 11.5 series or beyond 12.1.5 for the 12.1 series to incorporate these security fixes. In addition to patching, administrators should enforce strict role-based access control policies that limit who can execute administrative commands like CREATE WRAPPER. Principle of least privilege dictates that only a minimal set of highly trusted database administrators should have permission to define external data sources. Regular audits of wrapper configurations and connection strings are recommended to detect any unauthorized or suspicious entries. Furthermore, implementing network segmentation to isolate Db2 servers from direct internet exposure reduces the attack surface for remote exploitation attempts by authenticated users who may have compromised accounts.