CVE-2026-20095: Cisco IMC RCE Vulnerability

CVE-2026-20095 Overview

A command injection vulnerability exists in the web-based management interface of Cisco Integrated Management Controller (IMC). This security flaw allows an authenticated, remote attacker with admin-level privileges to perform command injection attacks on an affected system and execute arbitrary commands as the root user.

The vulnerability stems from improper validation of user-supplied input in the web management interface. An attacker could exploit this vulnerability by sending crafted commands to the web-based management interface of the affected software. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with root privileges.

Critical Impact

Despite the CVSS score indicating Medium severity, Cisco has assigned this vulnerability a Security Impact Rating (SIR) of High because additional security implications could occur once the attacker has become root on the affected system.

Affected Products

• Cisco Integrated Management Controller (IMC)
• Cisco IMC Web-based Management Interface
• Systems running vulnerable versions of Cisco IMC firmware

Discovery Timeline

• April 1, 2026 - CVE-2026-20095 published to NVD
• April 1, 2026 - Last updated in NVD database

Technical Details for CVE-2026-20095

Vulnerability Analysis

This command injection vulnerability (CWE-77) affects the web-based management interface of Cisco IMC. The vulnerability allows authenticated attackers with administrative privileges to inject and execute arbitrary operating system commands with root-level access.

The attack requires network access and valid administrative credentials to the Cisco IMC web interface. While the prerequisite of admin-level access might seem limiting, the ability to escalate from web interface administrator to full root shell access on the underlying operating system represents a significant security boundary violation. This escalation path enables attackers to gain persistent access, modify system configurations beyond the intended administrative scope, and potentially pivot to other systems.

Root Cause

The root cause of this vulnerability is improper validation of user-supplied input in the web-based management interface. Input fields that accept user data are not adequately sanitized before being passed to system command execution functions, allowing specially crafted input containing shell metacharacters or command sequences to be interpreted and executed by the underlying operating system.

Attack Vector

The attack vector for CVE-2026-20095 is network-based, requiring the attacker to have:

1. Network access to the Cisco IMC web-based management interface
2. Valid administrative credentials to authenticate to the interface
3. Knowledge of the vulnerable input fields or API endpoints

Once authenticated, the attacker can craft malicious input containing command injection payloads. These payloads bypass the insufficient input validation and are executed with root privileges on the underlying operating system. The attack does not require user interaction and can be executed remotely.

The vulnerability mechanism involves injecting operating system commands through web interface parameters that are improperly passed to shell execution contexts. Common command injection techniques such as command chaining (using characters like ;, &&, ||), command substitution (using backticks or $()), or pipe characters may be employed to break out of the intended command context and execute arbitrary commands.

For detailed technical information, refer to the Cisco Security Advisory.

Detection Methods for CVE-2026-20095

Indicators of Compromise

• Unusual process execution chains originating from web server processes on Cisco IMC systems
• Unexpected root-level command execution or shell spawning on affected devices
• Anomalous network connections initiated from Cisco IMC management interfaces
• Suspicious entries in system logs indicating command execution with shell metacharacters

Detection Strategies

• Monitor Cisco IMC system logs for unusual command execution patterns or authentication events followed by suspicious activity
• Implement network monitoring to detect anomalous traffic patterns to and from Cisco IMC management interfaces
• Deploy intrusion detection rules to identify command injection payloads in HTTP requests to management interfaces
• Review administrative access logs for unexpected or unauthorized authentication attempts

Monitoring Recommendations

• Enable comprehensive logging on Cisco IMC devices and forward logs to a centralized SIEM solution
• Configure alerts for root-level command execution that deviates from normal administrative operations
• Monitor for new user accounts, SSH keys, or scheduled tasks created on affected systems
• Implement behavioral analysis to detect post-exploitation activities such as lateral movement attempts

How to Mitigate CVE-2026-20095

Immediate Actions Required

• Review the Cisco Security Advisory for patch availability and apply updates immediately
• Restrict network access to Cisco IMC management interfaces to trusted administrative networks only
• Implement strong authentication and enforce multi-factor authentication where possible
• Audit administrative accounts and remove unnecessary admin-level privileges
• Enable comprehensive logging and monitor for suspicious activity

Patch Information

Cisco has released a security advisory for this vulnerability. Administrators should consult the Cisco Security Advisory for specific patch versions and upgrade paths. Apply the latest firmware updates to all affected Cisco IMC deployments as soon as possible.

Workarounds

• Limit access to the Cisco IMC web interface to trusted IP addresses using access control lists (ACLs)
• Place Cisco IMC management interfaces on isolated management networks not accessible from general user networks
• Implement a bastion host or jump server for administrative access to reduce the attack surface
• Regularly review and audit administrative user accounts to ensure only authorized personnel have access

# Example ACL configuration to restrict IMC management access
# Apply network-level restrictions to limit access to management interface
# Allow only trusted management subnet to access IMC
access-list IMC_MGMT_ACL permit ip 10.0.100.0/24 host 192.168.1.100
access-list IMC_MGMT_ACL deny ip any host 192.168.1.100