CVE-2026-10109 in DB2
Summary
by MITRE • 06/30/2026
IBM Db2 11.5.0 through 11.5.9, and 12.1.0 through 12.1.4 is vulnerable to remote code execution due to improper pre-auth DRDA handshake handling.
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Analysis
by VulDB Data Team • 07/01/2026
This vulnerability exists in IBM Db2 database server versions 11.5.0 through 11.5.9 and 12.1.0 through 12.1.4, representing a critical security flaw that allows remote code execution without authentication. The issue stems from improper handling during the Distributed Relational Database Architecture DRDA handshake process, which occurs before any authentication mechanisms are engaged. This pre-authentication vulnerability creates an attack surface where malicious actors can exploit the database server's initial connection negotiation phase to execute arbitrary code on the target system. The flaw specifically manifests in how Db2 processes incoming connection requests during the DRDA protocol initialization, where insufficient input validation and sanitization permits specially crafted malformed packets to trigger unexpected behavior within the database engine.
The technical implementation of this vulnerability involves the database server's failure to properly validate data received during the initial DRDA handshake sequence. When a client establishes a connection to the Db2 server, the system performs a series of protocol negotiation steps before authentication occurs. During these early stages, the server processes various parameters and flags that define the connection characteristics. An attacker can manipulate these parameters in ways that cause the server to execute unintended code paths, potentially leading to complete system compromise. This type of vulnerability falls under CWE-129, Input Validation, and more specifically aligns with CWE-787, Out-of-bounds Write, when considering the memory corruption aspects of improper handshake handling. The vulnerability is particularly dangerous because it operates entirely outside the normal authentication boundaries, meaning that any user with network access to the database port can potentially exploit this flaw without needing valid credentials.
From an operational impact perspective, successful exploitation of this vulnerability allows attackers to achieve remote code execution on the Db2 server with the privileges of the database service account. This typically translates to elevated system-level access that could enable data exfiltration, lateral movement within the network, or complete system compromise depending on the underlying operating system and service configuration. The attack vector requires only network connectivity to the database port, making it particularly attractive to threat actors who may have discovered exposed Db2 instances through reconnaissance activities. Organizations running affected Db2 versions face significant risk of unauthorized access, data breaches, and potential regulatory compliance violations. The vulnerability can be exploited by attackers using various tools and techniques that craft specific DRDA protocol packets designed to trigger the memory corruption or control flow manipulation within the database server.
The mitigation strategy for this vulnerability involves immediate application of IBM's security patches and updates released specifically for this flaw. Organizations should prioritize upgrading their Db2 installations to versions that contain the necessary fixes for the DRDA handshake handling implementation. Additionally, network segmentation and access controls should be implemented to restrict direct network access to database ports from trusted sources only. The use of firewalls and intrusion detection systems can help monitor for suspicious DRDA protocol traffic patterns that might indicate exploitation attempts. Security teams should also consider implementing database activity monitoring solutions to detect anomalous connection behaviors or unusual query patterns that could indicate compromise. From a defensive standpoint, this vulnerability aligns with ATT&CK technique T1190, Exploit Public-Facing Application, and T1071.004, Application Layer Protocol: DNS, when attackers attempt to leverage exposed database services for initial access or lateral movement within target networks. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of affected Db2 versions that may have been overlooked during initial patching efforts.