CVE-2026-16892 in IBM
Summary
by MITRE • 09/04/2026
IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to bypass security restrictions due to improper authentication during service-name matching.
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Analysis
by VulDB Data Team • 09/04/2026
The vulnerability identified in IBM i operating system versions 7.3 through 7.6 represents a critical flaw within the network communication subsystem responsible for handling service name resolution and validation. This issue stems from an implementation error where the mechanism used to match incoming connection requests against defined security policies fails to strictly enforce authentication requirements during specific stages of the handshake or routing process. Specifically, when the system processes service-name matching logic, it allows a remote authenticated attacker to exploit gaps in credential verification protocols. The core technical flaw lies in the improper handling of identity validation relative to service identifiers, which creates an opportunity for privilege escalation or unauthorized access by bypassing intended security restrictions that should have been enforced prior to granting resource access.
From a technical perspective, this vulnerability is classified under CWE-287, Improper Authentication, as it involves a failure in the system's ability to correctly verify the identity of a user attempting to gain access to resources or perform actions within the operating environment. The attacker leverages their existing authenticated status but manipulates the service-name matching parameters to trick the security subsystem into granting permissions that exceed those associated with their current role. This bypass mechanism likely exploits edge cases in how the IBM i kernel maps logical service names to physical network endpoints and applies access control lists, allowing traffic or commands intended for restricted services to be processed as if they were authorized for less privileged contexts.
The operational impact of this vulnerability is significant for organizations relying on IBM i systems for mission-critical business applications such as ERP, financial processing, and supply chain management. An attacker who successfully exploits this flaw could gain unauthorized access to sensitive data, modify system configurations, or execute arbitrary commands with elevated privileges. This compromises the confidentiality, integrity, and availability of the affected systems. In a multi-tenant environment or one where different departments share infrastructure, such a breach could lead to lateral movement across network segments, potentially exposing proprietary intellectual property and customer information to external threats or insider adversaries seeking to escalate their access levels beyond what is contractually or administratively permitted.
To mitigate this risk, organizations must immediately apply the latest security patches provided by IBM for all affected versions of IBM i 7.3, 7.4, 7.5, and 7.6. These updates address the underlying logic errors in the service-name matching routine that allow authentication bypasses. In addition to patching, administrators should review network segmentation strategies to ensure that critical services are not directly exposed to untrusted networks without additional layers of security such as firewalls or intrusion detection systems. Implementing strict access control policies and regularly auditing user permissions can further reduce the attack surface. Security teams should also monitor for anomalous login patterns or unauthorized service accesses, which may indicate exploitation attempts aligned with ATT&CK techniques related to privilege escalation and credential abuse within enterprise environments.