CVE-2026-20097: Cisco IMC RCE Vulnerability

CVE-2026-20097 Overview

A vulnerability exists in the web-based management interface of Cisco Integrated Management Controller (IMC) that could allow an authenticated, remote attacker with admin-level privileges to execute arbitrary code as the root user. This vulnerability stems from improper validation of user-supplied input to the web-based management interface. An attacker could exploit this vulnerability by sending crafted HTTP requests to an affected device, potentially gaining complete control over the underlying operating system.

Critical Impact

Despite the medium CVSS score, Cisco has assigned this vulnerability a Security Impact Rating (SIR) of High because successful exploitation grants root-level access to the underlying operating system, enabling additional security implications including full system compromise.

Affected Products

• Cisco Integrated Management Controller (IMC) - web-based management interface
• Cisco devices utilizing IMC for remote management
• Systems with exposed IMC web interfaces

Discovery Timeline

• 2026-04-01 - CVE CVE-2026-20097 published to NVD
• 2026-04-01 - Last updated in NVD database

Technical Details for CVE-2026-20097

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-Bounds Write), indicating a memory corruption flaw where the application writes data past the intended buffer boundary. The vulnerability resides in the web-based management interface of Cisco IMC, which handles HTTP requests from authenticated administrators.

The flaw allows an attacker with administrative credentials to craft malicious HTTP requests that bypass input validation mechanisms. When processed by the vulnerable interface, these requests trigger an out-of-bounds write condition that can be leveraged to execute arbitrary code with root privileges on the underlying operating system.

While exploitation requires administrative authentication, the impact is significant as it elevates already-privileged access to complete root-level control of the device, potentially enabling persistence mechanisms, lateral movement, or complete infrastructure compromise in environments where IMC manages multiple systems.

Root Cause

The vulnerability exists due to improper validation of user-supplied input to the web-based management interface. The application fails to adequately sanitize or validate data received through HTTP requests, allowing specially crafted input to trigger an out-of-bounds write condition. This memory corruption flaw can then be exploited to achieve arbitrary code execution with the highest system privileges.

Attack Vector

The attack is conducted over the network and requires authenticated access with administrative privileges to the Cisco IMC web-based management interface. The attacker must craft specific HTTP requests containing malicious payloads designed to trigger the out-of-bounds write vulnerability. Upon successful exploitation, the attacker gains the ability to execute arbitrary commands as the root user on the underlying operating system.

The exploitation flow involves:

1. Authenticating to the IMC web interface with admin credentials
2. Sending specially crafted HTTP requests to vulnerable endpoints
3. Triggering the out-of-bounds write condition
4. Achieving arbitrary code execution as root

For technical details on exploitation mechanics, refer to the Cisco Security Advisory.

Detection Methods for CVE-2026-20097

Indicators of Compromise

• Unusual HTTP requests to the Cisco IMC web management interface containing malformed or oversized parameters
• Unexpected processes spawning from IMC web server components with root privileges
• Anomalous system commands executed on IMC-managed devices that deviate from normal administrative operations
• Log entries showing authentication followed by suspicious POST requests to management endpoints

Detection Strategies

• Monitor and analyze HTTP traffic to Cisco IMC management interfaces for malformed or suspicious request patterns
• Implement network intrusion detection rules to identify crafted HTTP requests targeting IMC endpoints
• Deploy endpoint detection capabilities on systems running Cisco IMC to identify unauthorized root-level process execution
• Review IMC access logs for unusual administrative activity patterns or requests from unexpected sources

Monitoring Recommendations

• Enable detailed logging on Cisco IMC web interfaces and forward logs to a centralized SIEM solution
• Implement alerting for any new root-level processes spawned on IMC-managed infrastructure
• Monitor network traffic to IMC management ports (typically HTTPS/443) for anomalous request sizes or frequencies
• Establish baseline administrative behavior and alert on deviations from normal patterns

How to Mitigate CVE-2026-20097

Immediate Actions Required

• Review the Cisco Security Advisory for affected version information and available patches
• Restrict network access to Cisco IMC web management interfaces to trusted management networks only
• Audit administrative accounts with access to IMC and ensure principle of least privilege
• Implement network segmentation to isolate IMC management interfaces from general network traffic
• Enable multi-factor authentication for administrative access where supported

Patch Information

Cisco has released a security advisory addressing this vulnerability. Administrators should consult the Cisco Security Advisory cisco-sa-cimc-cmd-inj-3hKN3bVt for specific patch information, affected software versions, and upgrade guidance. It is recommended to apply the vendor-supplied patches as soon as possible after appropriate testing.

Workarounds

• Implement strict access control lists (ACLs) limiting IMC web interface access to specific trusted management IP addresses
• Deploy a web application firewall (WAF) in front of IMC interfaces to filter potentially malicious HTTP requests
• Consider disabling the web-based management interface if not required and use alternative management methods such as CLI over SSH
• Implement network-level controls to require VPN connectivity before accessing management interfaces

# Example ACL configuration to restrict IMC access
# Limit management interface access to trusted subnet only
access-list IMC_MGMT_ACL permit tcp 10.10.10.0/24 host 192.168.1.100 eq 443
access-list IMC_MGMT_ACL deny tcp any host 192.168.1.100 eq 443