CVE-2026-87684 in Fabric OS
Summary
by MITRE • 10/08/2026
A stack-based buffer overflow vulnerability exists in the SNMP daemon request handling of Brocade Fabric versions before 10.0.1. When processing an incoming SNMPv3 packet, an internal statistics gathering handler copies user-supplied context name data into a fixed-size buffer without properly validating the length of the string. A remote, unauthenticated attacker (under default configuration) can exploit this vulnerability by sending a specially crafted SNMPv3 packet, leading to memory corruption, daemon crash (Denial of Service), or potential arbitrary code execution.
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Analysis
by VulDB Data Team • 10/08/2026
The identified vulnerability represents a critical security flaw within the Simple Network Management Protocol daemon present in Brocade Fabric operating systems prior to version 10.0.1. This specific weakness is classified as a stack-based buffer overflow, which occurs when data exceeding the allocated memory capacity of a fixed-size buffer on the call stack is written without adequate bounds checking. In this particular instance, the vulnerability resides within an internal statistics gathering handler responsible for processing incoming SNMPv3 packets. The core technical failure involves the improper validation of string lengths associated with user-supplied context name fields. When the daemon receives these requests, it copies the provided data directly into a statically allocated buffer on the stack without verifying whether the input length fits within the predefined limits. This lack of boundary verification allows an attacker to inject payloads that overwrite adjacent memory locations, corrupting the control flow of the application and potentially overwriting critical return addresses or function pointers stored on the stack.
From an operational perspective, this vulnerability poses a severe risk due to its remote exploitability under default configurations. An unauthenticated attacker can leverage this flaw by transmitting specially crafted SNMPv3 packets to the target system. The immediate consequence of successful exploitation is typically memory corruption that leads to the termination or crash of the SNMP daemon process, resulting in a Denial of Service condition for network management operations. However, given the nature of stack-based buffer overflows, there exists a significant potential for arbitrary code execution if an attacker can precisely control the overflowed data and bypass existing mitigations such as non-executable stacks or address space layout randomization. This capability allows the adversary to execute malicious commands with the privileges of the compromised service account, potentially leading to full system compromise and lateral movement within the network infrastructure.
The technical characteristics of this vulnerability align closely with Common Weakness Enumeration identifier CWE-120, which describes buffer copies without checks for overflow along a stack frame. Furthermore, the exploitation vector corresponds to MITRE ATT&CK technique T1498, specifically Network Denial of Service via service disruption or resource exhaustion through memory corruption attacks. The ability to execute arbitrary code also maps to techniques involving remote command execution and privilege escalation depending on the context in which the daemon operates. To mitigate this risk, organizations must ensure that all Brocade Fabric devices are upgraded to version 10.0.1 or later where these input validation checks have been implemented. Additionally, implementing network segmentation to restrict SNMP access to trusted management stations only can reduce the attack surface by preventing unauthenticated remote actors from reaching the vulnerable service endpoints.