CVE-2026-94583 in Fabric OS
Summary
by MITRE • 10/08/2026
A race condition vulnerability exists in the request processing logic of the REST management interface on Brocade Fabric OS versions before 10.0.1. When handling concurrent incoming network management FCIP requests, a timing window exists between when a request populates the address variable and when the service constructs and returns the response context. As a result, the first request adopts the modified context, causing the service to return sensitive management details or configuration data belonging to the second context back to the original requester.
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Analysis
by VulDB Data Team • 10/08/2026
The vulnerability identified in Brocade Fabric OS versions prior to 10.0.1 represents a critical race condition within the RESTful management interface's request processing logic, specifically affecting Fibre Channel over IP (FCIP) operations. This flaw stems from improper synchronization mechanisms when handling concurrent network management requests. The core technical deficiency lies in the temporal gap between the initialization of address variables for an incoming request and the subsequent construction of the response context by the service handler. In a properly secured system, each thread or process managing a specific client connection should maintain strict isolation of its state data throughout the lifecycle of that transaction. However, due to this timing window, shared resources are accessed without adequate locking or atomicity guarantees, allowing one request's execution flow to interfere with another's pending operation.
When multiple FCIP management requests arrive simultaneously, the operating system schedules these threads in an interleaved manner. The vulnerability exploits a specific sequence where Request A begins processing and populates its address variable. Before Request A completes the construction of its response context, Request B arrives or advances further in execution, modifying shared memory structures or variables that were intended to be isolated for Request A. Consequently, when Request A proceeds to finalize its output, it inadvertently utilizes the modified state associated with Request B's context rather than its own original parameters. This results in a classic case of insecure direct object reference combined with race condition logic, where the service returns sensitive management details or configuration data belonging to one user or session back to another unrelated requester who initiated the first request.
The operational impact of this vulnerability is severe, primarily centering on unauthorized information disclosure and potential privilege escalation through misconfiguration exposure. An authenticated attacker can leverage this timing window by sending a high volume of concurrent requests designed to maximize the probability of hitting the race condition. By doing so, they can extract sensitive network topology data, security policies, authentication credentials, or other critical configuration parameters intended for different administrative sessions. This breach compromises the confidentiality and integrity of the storage area network management plane. In enterprise environments where Brocade switches manage large-scale fabric topologies, such exposure could allow an attacker to map out the entire infrastructure, identify high-value targets, or craft more sophisticated attacks based on revealed architectural weaknesses.
From a classification perspective, this vulnerability aligns with CWE-362, which defines race conditions involving shared resources without proper synchronization. It also relates closely to CWE-209, as it generates information about an error condition that may be exploitable by attackers, and CWE-345, indicating insufficient verification of data authenticity or state consistency before use. In the context of the MITRE ATT&CK framework, this behavior is consistent with techniques found under T1078, Valid Accounts, if exploited for lateral movement after initial access, but more directly maps to information gathering phases where an adversary seeks to understand the environment's structure and security controls through unauthorized data retrieval. The exploitation requires network-level access to the management interface and typically involves authenticated sessions, placing it within the scope of attacks that target administrative interfaces rather than unauthenticated remote code execution vectors.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The primary and most effective mitigation is to upgrade Brocade Fabric OS to version 10.0.1 or later, where this race condition has been addressed by the vendor through improved synchronization primitives in the REST API handler. For environments where immediate patching is not feasible due to operational constraints, network segmentation should be enforced to restrict access to the management interface exclusively from trusted administrative subnets using firewalls or VLAN isolation. Additionally, implementing rate limiting on the REST API can reduce the likelihood of concurrent requests hitting the specific timing window simultaneously, thereby mitigating the exploitability of the race condition until a patch is applied. Security monitoring tools should also be configured to detect anomalous patterns of high-frequency management interface access that may indicate an active exploitation attempt.