CVE-2020-3167 in FXOS
Summary
by MITRE
A vulnerability in the CLI of Cisco FXOS Software and Cisco UCS Manager Software could allow an authenticated, local attacker to execute arbitrary commands on the underlying operating system (OS). The vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by including crafted arguments to specific commands. A successful exploit could allow the attacker to execute arbitrary commands on the underlying OS with the privileges of the currently logged-in user for all affected platforms excluding Cisco UCS 6400 Series Fabric Interconnects. On Cisco UCS 6400 Series Fabric Interconnects, the injected commands are executed with root privileges.
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Analysis
by VulDB Data Team • 08/12/2026
The vulnerability identified as CVE-2020-3167 represents a critical command injection flaw within the command line interface of Cisco FXOS Software and Cisco UCS Manager Software. This security weakness stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied arguments before processing them within the system's underlying operating environment. The vulnerability affects multiple Cisco networking and data center platforms, creating a significant attack surface for authenticated local adversaries who can leverage this flaw to escalate their privileges and execute unauthorized operations.
The technical exploitation of this vulnerability occurs through carefully crafted arguments that are passed to specific commands within the CLI interface. When these malformed inputs are processed without proper validation, they can be interpreted by the system as additional commands to execute rather than simple parameters. This insufficient sanitization creates a pathway for command injection attacks where an attacker can append malicious payloads to legitimate commands, causing the system to execute unintended operations. The vulnerability's impact varies depending on the target platform, with most affected systems allowing execution with the privileges of the currently logged-in user, while Cisco UCS 6400 Series Fabric Interconnects present an even more severe risk due to root-level execution privileges.
The operational implications of this vulnerability extend beyond simple privilege escalation, as it provides attackers with persistent access to critical infrastructure components. Attackers can leverage this flaw to modify system configurations, install malicious software, access sensitive data, or establish backdoor access points within the network infrastructure. The authenticated nature of the attack means that adversaries must already have legitimate access credentials, but this requirement does not mitigate the severity since the privilege escalation allows for operations that would otherwise be restricted. This vulnerability particularly impacts enterprise networks where Cisco UCS systems serve as core infrastructure components for data center operations and network fabric management.
Security professionals should implement immediate mitigation strategies focusing on access controls and system hardening measures. The primary recommendation involves restricting physical and logical access to affected systems, implementing strict administrative access controls, and monitoring for unusual command execution patterns. Network segmentation and privilege management should be enhanced to limit the potential damage from successful exploitation. Additionally, organizations should consider applying Cisco's security advisories and patches as soon as they become available, while also implementing behavioral monitoring to detect anomalous command execution patterns that may indicate exploitation attempts. This vulnerability aligns with CWE-77 and CWE-94 categories related to command injection and code execution flaws, and represents a technique commonly mapped to ATT&CK tactic of privilege escalation through command execution.