CVE-2026-12670 in MQ Operator
Summary
by MITRE • 10/19/2026
IBM MQ could allow an authenticated attacker to cause a denial of service through a specially crafted message that triggers excessive memory operations during character set conversion.
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Analysis
by VulDB Data Team • 10/19/2026
The vulnerability in IBM MQ represents a significant risk to the availability and integrity of enterprise messaging infrastructure, specifically targeting the component responsible for handling character set conversions within received messages. This flaw allows an authenticated attacker to exploit improper input validation or resource management logic when processing specially crafted data payloads. By submitting a message designed to trigger excessive memory operations during the translation between different character encodings, the attacker can induce a state of resource exhaustion on the affected system. The core technical issue lies in how the middleware processes variable-length strings or complex encoding sequences that require iterative conversion routines which fail to enforce strict bounds checking or limits on computational complexity.
From a technical perspective, this vulnerability is classified under CWE-400, which denotes uncontrolled resource consumption, and more specifically relates to CWE-789, where memory allocation occurs without proper restriction based on external input size. When the character set conversion engine encounters malformed or excessively large encoding sequences that it attempts to process iteratively, it may enter an infinite loop or allocate progressively larger blocks of memory in a futile attempt to resolve the invalid data structure. This behavior leads to rapid depletion of available system resources, including RAM and CPU cycles dedicated to message processing threads. The attack vector requires authentication, meaning the attacker must possess valid credentials for the IBM MQ queue manager, which limits the scope but does not diminish the severity given that insider threats or compromised service accounts are common vectors in enterprise environments.
The operational impact of this denial-of-service condition is severe, as it can render critical business applications unable to send or receive messages through the affected broker. In high-throughput messaging scenarios, even a single successful exploit attempt can cause latency spikes for legitimate traffic before the system becomes unresponsive and requires manual restart or resource recovery. This disruption affects service level agreements dependent on reliable message delivery and can lead to cascading failures in downstream systems that rely on real-time data ingestion from IBM MQ queues. The lack of automatic mitigation mechanisms means that administrators must intervene manually, leading to extended downtime periods during which business continuity is compromised.
To mitigate this risk, organizations should ensure that their IBM MQ installations are updated with the latest security patches provided by IBM, which typically include fixes for input validation and resource limit enforcement in character conversion routines. Additionally, implementing strict access controls via Role-Based Access Control (RBAC) ensures that only trusted users can submit messages to sensitive queues, thereby reducing the attack surface. Network segmentation strategies should also be employed to isolate MQ infrastructure from less secure network zones, preventing unauthorized entities from reaching even authenticated endpoints if credential theft occurs. Monitoring tools should be configured to detect anomalous spikes in memory usage or CPU consumption associated with message processing activities, allowing for early detection and response before a full denial of service is realized. This vulnerability aligns with ATT&CK technique T1498, Network Denial of Service, where the attacker leverages specific application logic flaws rather than brute force to disrupt services.