CVE-2026-87683 in Fabric OS
Summary
by MITRE • 10/08/2026
Multiple stack-based buffer overflow vulnerabilities exist in the REST API management component of Brocade Fabric OS versions prior to 10.0.1. When processing API request payloads (such as device configuration attributes or port mapping requests) the REST API service fails to properly validate incoming array counts and string lengths against internal buffer capacities. An authenticated attacker with REST API access can transmit crafted, oversized request parameters to induce memory corruption on the execution stack. This may result in a denial-of-service condition (daemon crash) or potential arbitrary code execution within the management process context.
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Analysis
by VulDB Data Team • 10/08/2026
The vulnerability identified involves multiple stack-based buffer overflow conditions located within the REST API management component of Brocade Fabric OS versions prior to 10.0.1. This specific subsystem is responsible for handling incoming HTTP requests that configure network devices or map ports, serving as a critical interface for administrative operations. The core technical flaw stems from an improper validation mechanism where the service fails to rigorously check the size of incoming array counts and string lengths against the allocated internal buffer capacities. When processing API request payloads, such as those containing device configuration attributes or port mapping data, the application assumes that input dimensions are within safe limits without performing adequate boundary checks. This lack of sanitization allows an attacker to supply crafted parameters with oversized values that exceed the fixed-size buffers reserved on the execution stack during function calls.
From a technical perspective, this flaw aligns closely with CWE-121, which classifies stack-based buffer overflows resulting from insufficient bounds checking on input data. When an authenticated user transmits these malformed request parameters, the excess data spills beyond the allocated memory space for local variables and return addresses stored on the stack. This memory corruption can overwrite critical control flow information, such as the saved instruction pointer or frame pointers. Depending on the specific payload structure and memory layout of the target system, this overwriting may lead to a denial-of-service condition characterized by the crash of the REST API daemon process due to an illegal memory access exception. Alternatively, if the attacker can precisely control the overwritten data, it enables arbitrary code execution within the context of the management process, which typically runs with elevated privileges necessary for network administration tasks.
The operational impact of this vulnerability is severe given its location in a core infrastructure component. An authenticated attacker who possesses valid credentials to access the REST API interface can exploit these flaws remotely or locally depending on network segmentation policies. The ability to crash the daemon disrupts management capabilities, potentially leading to a loss of visibility and control over the fabric switches. More critically, successful exploitation for arbitrary code execution could allow an adversary to gain full administrative control over the affected switch. This compromise facilitates further lateral movement within the data center network, enabling actions such as traffic interception, configuration tampering, or pivoting to other connected systems. The vulnerability is categorized under MITRE ATT&CK technique T1059, specifically Command and Scripting Interpreter sub-techniques if used for initial access via API calls, and potentially T1203 for exploitation of client software components if the attack vector involves complex payload delivery mechanisms.
Mitigation strategies primarily involve upgrading to Brocade Fabric OS version 10.0.1 or later, where these validation checks have been implemented to ensure input sizes are strictly bounded by buffer capacities. In environments where immediate patching is not feasible, network segmentation should be enforced to restrict access to the REST API management interface exclusively from trusted administrative subnets. Additionally, implementing strict rate limiting and input filtering at the perimeter firewall or load balancer can help mitigate the risk of exploitation attempts by blocking excessively large payloads before they reach the vulnerable application layer. Security teams should also monitor for unusual spikes in error logs related to the REST service daemon crashes as an indicator of potential exploitation activity.