CVE-2026-20092: Cisco Intersight Privilege Escalation

CVE-2026-20092 Overview

A privilege escalation vulnerability exists in the read-only maintenance shell of Cisco Intersight Virtual Appliance. This vulnerability allows an authenticated, local attacker with administrative privileges to elevate their access to root on the virtual appliance. The flaw stems from improper file permissions on configuration files for system accounts within the maintenance shell.

Critical Impact

Successful exploitation allows attackers to gain full root control of the Cisco Intersight Virtual Appliance, enabling access to sensitive information, modification of workloads and configurations on the host system, and potential denial of service (DoS) conditions.

Affected Products

• Cisco Intersight Virtual Appliance (maintenance shell component)

Discovery Timeline

• 2026-01-21 - CVE-2026-20092 published to NVD
• 2026-01-21 - Last updated in NVD database

Technical Details for CVE-2026-20092

Vulnerability Analysis

This vulnerability (CWE-732: Incorrect Permission Assignment for Critical Resource) enables local privilege escalation through manipulation of improperly secured system files. An attacker who has already obtained read-only administrator access to the maintenance shell can exploit misconfigured file permissions to escalate their privileges to root level access.

The attack requires local access and high privileges as a prerequisite, meaning an attacker must first compromise an administrative account before exploitation is possible. However, once root access is achieved, the attacker gains complete control over the virtual appliance infrastructure, including the ability to access sensitive data, alter system configurations, modify workloads, and disrupt service availability.

Root Cause

The vulnerability originates from improper file permissions assigned to configuration files for system accounts within the Cisco Intersight Virtual Appliance maintenance shell. These misconfigured permissions allow read-only administrators—who should have restricted access—to manipulate system files that control privilege assignments.

Attack Vector

The attack vector is local, requiring the attacker to have existing authenticated access to the maintenance shell as a read-only administrator. From this position, the attacker can:

1. Access the maintenance shell with read-only administrative credentials
2. Identify and locate configuration files with improper permissions
3. Manipulate these system files to grant elevated (root) privileges to their account
4. Execute commands with full root-level access on the virtual appliance

The exploitation does not require user interaction and can be performed with low attack complexity once the attacker has the required local administrative access. For detailed technical information, refer to the Cisco Security Advisory.

Detection Methods for CVE-2026-20092

Indicators of Compromise

• Unexpected privilege changes for maintenance shell user accounts
• Unauthorized modifications to system configuration files within the appliance
• Evidence of root-level command execution by read-only administrator accounts
• Anomalous file permission changes on critical system configuration files

Detection Strategies

• Monitor authentication logs for maintenance shell access patterns and privilege usage anomalies
• Implement file integrity monitoring (FIM) on critical system configuration files to detect unauthorized changes
• Review audit logs for unexpected privilege elevation events or sudo usage by read-only accounts
• Deploy endpoint detection solutions to identify suspicious local privilege escalation attempts

Monitoring Recommendations

• Enable comprehensive logging for all maintenance shell access and administrative activities
• Configure alerts for file permission modifications on system account configuration files
• Establish baseline behavior for administrative accounts and alert on deviations
• Regularly audit user privileges and access levels within the Intersight Virtual Appliance environment

How to Mitigate CVE-2026-20092

Immediate Actions Required

• Review the Cisco Security Advisory for official guidance and patches
• Audit all accounts with access to the maintenance shell and verify their privilege levels
• Restrict access to the maintenance shell to only essential personnel
• Monitor for any signs of exploitation or unauthorized privilege changes

Patch Information

Cisco has published a security advisory addressing this vulnerability. Administrators should consult the Cisco Security Advisory for specific patch versions, upgrade paths, and remediation instructions applicable to their deployment.

Workarounds

• Limit maintenance shell access to only trusted, verified administrators until patches are applied
• Implement strict role-based access controls to minimize the number of accounts with administrative privileges
• Deploy additional monitoring on file permission changes and privilege escalation events
• Consider network segmentation to isolate the virtual appliance from unnecessary access paths

Refer to the official Cisco documentation for any vendor-recommended temporary mitigations or configuration hardening guidance.