CVE-2026-4622: NEC Aterm Series RCE Vulnerability

CVE-2026-4622 Overview

CVE-2026-4622 is an OS Command Injection vulnerability (CWE-78) affecting NEC Platforms, Ltd. Aterm Series network devices. This vulnerability allows an attacker to execute arbitrary operating system commands via network access, potentially leading to complete device compromise.

Critical Impact

Successful exploitation enables attackers to execute arbitrary OS commands on vulnerable NEC Aterm Series devices, potentially resulting in full system compromise, unauthorized access to network infrastructure, and lateral movement within affected environments.

Affected Products

• NEC Platforms, Ltd. Aterm Series devices

Discovery Timeline

• 2026-03-27 - CVE-2026-4622 published to NVD
• 2026-03-30 - Last updated in NVD database

Technical Details for CVE-2026-4622

Vulnerability Analysis

This vulnerability stems from improper sanitization of user-supplied input before it is passed to operating system command execution functions within the NEC Aterm Series firmware. When network-accessible functions process specially crafted input, malicious commands can be injected and executed with the privileges of the underlying device operating system.

The attack requires network access to vulnerable management interfaces. While the attack complexity is high and requires elevated privileges along with some user interaction, successful exploitation leads to complete compromise of confidentiality, integrity, and availability of the affected device.

Root Cause

The root cause is classified under CWE-78 (Improper Neutralization of Special Elements used in an OS Command). The vulnerable code fails to properly validate, filter, or escape special characters and command separators in user-controlled input before incorporating it into operating system commands. This allows attackers to break out of the intended command context and inject additional malicious commands.

Attack Vector

The attack vector is network-based, meaning exploitation can occur remotely without physical access to the device. The attacker must craft malicious input containing OS command injection payloads (such as command separators like ;, |, &&, or backticks) and submit them through vulnerable network interfaces on the Aterm Series devices. The injected commands execute within the device's operating system context, potentially allowing full administrative control.

The vulnerability mechanism involves improper input handling in network-accessible functions. Technical implementation details are available in the NEC Security Advisory NV26-001.

Detection Methods for CVE-2026-4622

Indicators of Compromise

• Unexpected command execution or shell spawning processes on Aterm Series devices
• Anomalous network traffic patterns to/from device management interfaces
• Unauthorized configuration changes or new user accounts on affected devices
• Unusual outbound connections from network equipment to unknown external hosts

Detection Strategies

• Monitor network traffic for command injection patterns in HTTP requests targeting Aterm device management interfaces
• Implement intrusion detection rules to identify common OS command injection payloads (;, |, &&, backticks, $()) in device-bound traffic
• Deploy network behavior analysis to detect anomalous activity from network infrastructure devices
• Review device logs for failed or successful unauthorized access attempts

Monitoring Recommendations

• Enable comprehensive logging on all NEC Aterm Series devices and forward logs to centralized SIEM
• Implement network segmentation to isolate management interfaces from untrusted networks
• Monitor for firmware integrity changes or unauthorized modifications on affected devices
• Set up alerts for administrative actions on network devices outside of authorized change windows

How to Mitigate CVE-2026-4622

Immediate Actions Required

• Review the NEC Security Advisory NV26-001 for affected product versions and available patches
• Restrict network access to device management interfaces using firewall rules or access control lists
• Disable unnecessary network services and administrative interfaces on affected devices
• Implement network segmentation to limit exposure of vulnerable management interfaces

Patch Information

NEC Platforms, Ltd. has published security advisory NV26-001 addressing this vulnerability. Administrators should consult the official NEC security advisory for specific patch information, affected firmware versions, and update procedures for their Aterm Series devices.

Workarounds

• Restrict management interface access to trusted IP addresses only using ACLs
• Place affected devices behind a firewall that blocks external access to management ports
• Implement VPN requirements for remote administrative access to vulnerable devices
• Disable web-based management interfaces if not required for operations

# Example: Restrict management access via firewall (adjust ports as needed)
# Block external access to common management ports
iptables -A INPUT -p tcp --dport 80 -s ! 10.0.0.0/8 -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 10.0.0.0/8 -j DROP
iptables -A INPUT -p tcp --dport 23 -s ! 10.0.0.0/8 -j DROP