CVE-2026-94579 in Fabric OS
Summary
by MITRE • 10/08/2026
An OS command injection vulnerability exists in the PAM (Pluggable Authentication Module) session cleanup routines during SSH session termination on Brocade Fabric OS versions before 9.2.2d and 10.0.0 through 10.0.0a1. An authenticated user authenticating via an external directory or AAA service whose username or profile identifier contains shell metacharacters can trigger arbitrary command execution with root privileges when their remote SSH session closes.
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Analysis
by VulDB Data Team • 10/08/2026
The vulnerability described constitutes a critical OS command injection flaw within the Pluggable Authentication Module (PAM) session cleanup routines of Brocade Fabric Operating System, specifically affecting versions prior to 9.2.2d and ranging from 10.0.0 through 10.0.0a1. This security defect arises during the termination phase of Secure Shell sessions when an authenticated user connects via external directory services or Authentication Authorization and Accounting AAA infrastructure. The core technical flaw lies in the improper sanitization of input data, specifically usernames or profile identifiers that contain shell metacharacters such as semicolons, pipes, ampersands, or backticks. When a session ends, the system processes these unsanitized strings within command execution contexts without adequate validation, allowing an attacker to inject arbitrary operating system commands into the cleanup process.
From a technical perspective, this vulnerability is classified under CWE-78 Improper Neutralization of Special Elements used in an OS Command commonly known as OS Command Injection. The attack vector requires prior authentication, meaning it falls under CWE-286 Incorrect User Management where improper handling of user identifiers leads to privilege escalation. Because the PAM module operates with high-level system privileges during session teardown, any command injected through this pathway executes with root-level access on the target device. This effectively bypasses standard access controls and allows for complete compromise of the network infrastructure managed by the Fabric OS switch.
The operational impact of exploiting this vulnerability is severe, as it grants an authenticated attacker full control over the underlying operating system. An adversary could leverage this to exfiltrate sensitive configuration data, modify routing tables, install persistent backdoors, or pivot further into adjacent networks within the storage area network environment. The ability to execute commands with root privileges during session termination makes detection difficult because the malicious activity occurs in a background process that may not generate immediate alerting signals associated with active user sessions. This creates a stealthy persistence mechanism for attackers who have already gained initial access through compromised credentials or weak authentication policies.
Mitigation strategies must prioritize upgrading to Brocade Fabric OS version 9.2.2d or later, where the input validation logic in the PAM session cleanup routines has been corrected to properly neutralize shell metacharacters before processing. In environments where immediate patching is not feasible, administrators should enforce strict username policies that prohibit special characters and implement robust AAA configurations with rigorous identity verification. Additionally, deploying network segmentation and monitoring for anomalous command execution patterns during SSH disconnection events can help detect potential exploitation attempts in real-time according to MITRE ATT&CK techniques related to Command and Scripting Interpreter abuse.