CVE-2026-8652: Aterm OS Command Injection Vulnerability

CVE-2026-8652 Overview

CVE-2026-8652 is an OS Command Injection vulnerability [CWE-78] affecting NEC Aterm wireless routers. An authenticated attacker with administrator access to the product's web console can execute arbitrary operating system commands through the adjacent network. The flaw stems from improper neutralization of user-supplied input passed to shell command execution within the device's management interface.

NEC published advisory NV26-003 documenting the issue. The vulnerability requires high privileges and adjacent network access, which limits the attack surface to attackers who already possess administrative credentials or have compromised them through other means such as credential reuse or default password exposure.

Critical Impact
An attacker who gains administrator access to the Aterm web console can execute arbitrary OS commands on the router, leading to full device compromise and potential pivoting into adjacent network segments.

Affected Products

NEC Aterm wireless router series (see vendor advisory NV26-003 for specific models and firmware versions)
Devices exposing the administrative web console on the local network
Aterm products with unpatched firmware as identified by NEC

Discovery Timeline

2026-05-25 - CVE-2026-8652 published to NVD
2026-05-26 - Last updated in NVD database

Technical Details for CVE-2026-8652

Vulnerability Analysis

The vulnerability is classified as Improper Neutralization of Special Elements used in an OS Command [CWE-78]. The Aterm web console accepts input from authenticated administrators and passes it to underlying operating system command execution without adequate sanitization. An attacker can embed shell metacharacters or command separators into parameters processed by the console, causing the device to execute attacker-supplied commands with the privileges of the management process.

Because Aterm devices typically run management services as a privileged system account, successful exploitation yields control over routing, DNS configuration, firewall rules, and stored credentials. The attacker can persist on the device, intercept traffic, or use it as a foothold into the internal network.

Root Cause

The root cause is unsafe handling of administrator-supplied parameters within the embedded web console. Input destined for shell invocation is not filtered, escaped, or parameterized, allowing injected commands to be interpreted by the underlying shell.

Attack Vector

Exploitation requires adjacent network access, meaning the attacker must reach the router from the same Layer 2 broadcast domain such as Wi-Fi or local Ethernet. The attacker must also hold administrator credentials for the web console. Once authenticated, the attacker submits crafted requests containing shell metacharacters to vulnerable management endpoints. No verified public proof-of-concept code or exploit was available at the time of publication.

Detection Methods for CVE-2026-8652

Indicators of Compromise

Unexpected administrator logins to the Aterm web console from devices on the local network
Outbound connections from the router to unfamiliar internet hosts, indicating command-and-control activity
Unauthorized changes to DNS servers, port forwarding rules, or firewall configuration on the device
Anomalous DHCP or ARP behavior originating from the router

Detection Strategies

Monitor router administrative interfaces for authentication attempts from unusual MAC addresses or hostnames on the local segment
Inspect HTTP POST requests to the Aterm web console for shell metacharacters such as ;, |, &, backticks, or $() constructs
Correlate router configuration changes with the identity and source of the authenticated session

Monitoring Recommendations

Enable centralized logging from network infrastructure and forward logs to a SIEM for retention and analysis
Alert on configuration export, firmware modification, or shell-related strings appearing in administrative requests
Track devices connecting to the management VLAN and flag unauthorized endpoints attempting to reach the router console

How to Mitigate CVE-2026-8652

Immediate Actions Required

Apply the firmware update published by NEC in advisory NV26-003 as soon as it is available for the affected model
Change the Aterm administrator password and disable any reused or default credentials
Restrict access to the web console to a dedicated management network or trusted hosts only
Audit recent administrative sessions and configuration changes for signs of abuse

Patch Information

Refer to the NEC Security Advisory NV26-003 for the list of affected models and the corresponding fixed firmware versions. Install the vendor-supplied firmware update on every affected device.

Workarounds

Disable remote management features and ensure the web console is unreachable from untrusted Wi-Fi guest networks
Enforce strong, unique administrator passwords and rotate them after suspected compromise
Segment IoT and management traffic onto separate VLANs to reduce adjacent-network exposure

bash

# Example: restrict access to the router management interface using host firewall rules on adjacent clients
# Replace 192.0.2.1 with the Aterm management IP and 192.0.2.10 with the authorized admin workstation
iptables -A OUTPUT -d 192.0.2.1 -p tcp --dport 80 -s 192.0.2.10 -j ACCEPT
iptables -A OUTPUT -d 192.0.2.1 -p tcp --dport 80 -j DROP