CVE-2026-104364 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 could allow a local attacker to cause a denial of service due to improper input validation.
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Analysis
by VulDB Data Team • 10/12/2026
The vulnerability identified in IBM Db2 versions ranging from 11.5.0 through 11.5.9 and 12.1.0 through 12.1.5 represents a critical flaw rooted in insufficient validation of user-supplied input within the database management system's core processing routines. This defect allows an attacker who has already established local access to the host machine or possesses valid credentials for the Db2 instance to trigger a denial of service condition. The root cause lies in the application's failure to adequately sanitize, validate, or bounds-check specific inputs before they are processed by internal functions responsible for memory allocation and data structure manipulation. When malformed or excessively large input values are passed through these entry points, the system fails to handle them gracefully, leading to resource exhaustion, stack overflow conditions, or unhandled exceptions that cause the database service to crash or become unresponsive.
From a technical perspective, this issue aligns with CWE-20 Improper Input Validation and potentially CWE-400 Resource Exhaustion if the flaw leads to excessive consumption of system resources such as memory or CPU cycles during the processing phase. The vulnerability is classified as local in nature, meaning that remote exploitation over a network without prior authentication is not feasible under normal circumstances. An attacker must first compromise an account on the operating system level or obtain valid database credentials with sufficient privileges to interact with the vulnerable components of Db2. Once this access is achieved, the attacker can craft specific queries or API calls containing maliciously constructed parameters that exploit the validation gap. The resulting instability disrupts the availability of the database service, preventing legitimate users from accessing data and effectively halting business operations dependent on these systems.
The operational impact of this vulnerability extends beyond simple downtime to include potential data integrity risks if automatic recovery mechanisms are not properly configured or if crashes occur during critical transaction processing phases. In enterprise environments where IBM Db2 serves as a backend for mission-critical applications, such disruptions can lead to significant financial losses and reputational damage due to service unavailability. Furthermore, the presence of this vulnerability may serve as an initial foothold for attackers aiming to escalate privileges or pivot to other systems within the network if they are operating from a compromised host with local access. The lack of robust input validation suggests that the software does not adhere strictly to secure coding practices regarding boundary checks and error handling, which are essential components of defense-in-depth strategies in database management systems.
Mitigation for this vulnerability primarily involves applying the official patches or updates provided by IBM for the affected versions of Db2. Organizations should prioritize upgrading to a version where the input validation logic has been corrected to properly handle edge cases and malformed inputs without causing system instability. In addition to patching, implementing strict access controls is crucial; administrators should ensure that only authorized personnel have local shell access or database credentials with write privileges. Network segmentation can also help limit the blast radius by isolating Db2 instances from less trusted network zones. Regular security audits focusing on input validation patterns and adherence to standards such as CWE-20 will help identify similar weaknesses in other applications, ensuring a more resilient infrastructure against exploitation attempts that rely on improper handling of external data inputs.