CVE-2026-11381 in IBM
Summary
by MITRE • 09/18/2026
IBM MQ could allow an authenticated attacker to cause a denial of service or potentially execute arbitrary code due to improper validation of message distribution list structures.
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Analysis
by VulDB Data Team • 09/18/2026
The vulnerability identified in IBM Message Queue, commonly referred to as IBM MQ, represents a critical security flaw stemming from insufficient input validation within the application's handling of message distribution lists. This defect allows an authenticated attacker to exploit improperly structured data inputs that are processed by the queue manager during message routing operations. The core technical issue lies in how the software parses and validates the internal structures associated with distributing messages to multiple recipients or queues. When a specially crafted request containing malformed distribution list metadata is submitted, the application fails to adequately check for boundary conditions, buffer limits, or logical consistency within these data structures. This lack of rigorous validation creates an opportunity for memory corruption or logic bypasses that can destabilize the running process or allow for unauthorized code execution contexts.
From a technical perspective, this flaw aligns with CWE-20 Improper Input Validation and potentially CWE-119 Buffer Overflow if the malformed input leads to out-of-bounds writes in memory. The vulnerability is particularly dangerous because it requires authentication, meaning an attacker must first possess valid credentials or access tokens for the IBM MQ environment. However, once authenticated, the barrier to exploitation is significantly lowered compared to remote unauthenticated attacks. The attacker can manipulate the distribution list parameters to trigger undefined behavior within the queue manager's memory space. Depending on the specific version and configuration of IBM MQ, this could result in a segmentation fault causing a denial of service or, more severely, allow for arbitrary code execution if the memory corruption is precisely controlled to overwrite return addresses or function pointers.
The operational impact of this vulnerability is severe, affecting both availability and integrity within enterprise messaging infrastructures. In its least impactful form, an attacker can cause a denial of service by crashing the IBM MQ queue manager process. This disruption halts all message processing for connected applications, leading to significant downtime and potential data loss if messages in transit are not persisted safely before the crash occurs. For organizations relying on high-availability clusters or persistent messaging stores, this interruption can cascade into broader business logic failures, affecting financial transactions, supply chain updates, or real-time communications that depend on reliable message delivery.
In its most critical manifestation, the vulnerability enables arbitrary code execution with the privileges of the IBM MQ service account. If an attacker successfully exploits the memory corruption to execute malicious payloads, they gain a foothold within the server environment hosting the queue manager. This access can be leveraged for lateral movement across the network, privilege escalation if the service runs with elevated permissions, or data exfiltration from connected systems. The presence of this flaw undermines the trust model of IBM MQ as a secure middleware component, potentially exposing sensitive enterprise data and allowing attackers to establish persistent backdoors within critical infrastructure components.
Mitigation strategies must focus on immediate patching and access control hardening. Organizations running affected versions of IBM MQ should apply the latest security updates provided by IBM, which include fixes for this input validation flaw. Until patches are applied, it is crucial to restrict network access to IBM MQ ports strictly to trusted hosts and enforce strong authentication mechanisms such as TLS client certificates or robust LDAP/Active Directory integrations with least-privilege principles. Additionally, implementing deep packet inspection or web application firewalls that can detect anomalous message structures may provide a layer of defense against exploitation attempts. Security teams should also monitor system logs for unusual crashes or error codes related to queue manager processes and review access controls to ensure only authorized users have permission to create complex distribution lists or modify queue configurations.
This vulnerability is categorized under ATT&CK technique T1059 Command and Scripting Interpreter if code execution leads to shell access, and T1498 Network Denial of Service for the availability impact. It also relates to MITRE CWE-770 Allocation of Resources Without Limits or Throttling if resource exhaustion is a primary vector, though input validation remains the root cause. Continuous monitoring and adherence to secure coding practices in middleware configurations are essential to prevent similar vulnerabilities from being exploited in production environments.