CVE-2026-42062: ELECOM Wireless LAN Access Point RCE Flaw

CVE-2026-42062 Overview

CVE-2026-42062 is an unauthenticated OS command injection vulnerability affecting ELECOM wireless LAN access point devices. The flaw resides in how the device processes the username parameter during request handling. An attacker who sends a crafted request can execute arbitrary operating system commands on the device. No authentication is required, and the attack is reachable over the network. The issue is categorized under CWE-78, Improper Neutralization of Special Elements used in an OS Command.

Critical Impact

Remote, unauthenticated attackers can execute arbitrary OS commands on affected ELECOM access points, leading to full device compromise and pivot opportunities into adjacent networks.

Affected Products

• ELECOM wireless LAN access point devices (specific models listed in vendor advisory)
• Refer to the Elecom Security Update for the full list of impacted firmware versions
• Refer to the JVN #03037325 Advisory for additional model details

Discovery Timeline

• 2026-05-13 - CVE-2026-42062 published to NVD
• 2026-05-13 - Last updated in NVD database

Technical Details for CVE-2026-42062

Vulnerability Analysis

The vulnerability is a classic OS command injection issue tracked under CWE-78. The affected ELECOM access points accept a username parameter as part of a request handler and pass that value into an underlying shell or system call without proper neutralization of shell metacharacters. Because the vulnerable endpoint does not require authentication, any attacker who can reach the device's management interface over the network can trigger code execution.

Successful exploitation grants the attacker the privilege level of the web management process, which on consumer and small-business networking devices is typically root or an equivalent administrative account. From that position, an attacker can modify firmware, intercept Wi-Fi traffic, alter DNS settings, deploy persistent implants, or use the device as a foothold inside the LAN.

Root Cause

The root cause is the lack of input validation and sanitization on the username parameter before it is incorporated into an OS command. Shell metacharacters such as ;, |, `, and $() are not filtered or escaped, allowing attacker-controlled data to break out of the intended argument context and execute additional commands.

Attack Vector

The attack vector is network-based and requires no authentication or user interaction. An attacker sends a single crafted HTTP request to the affected device, embedding shell metacharacters within the username field. The device parses the request, constructs an OS command using the unsanitized input, and executes the attacker-supplied payload. The vulnerability is fully described in prose because no verified proof-of-concept code is published in the referenced advisories.

Detection Methods for CVE-2026-42062

Indicators of Compromise

• Unexpected outbound connections originating from ELECOM access point management IP addresses to unknown hosts
• Unusual configuration changes, new admin accounts, or modified DNS or firmware images on the device
• HTTP requests targeting the device's authentication or login endpoints containing shell metacharacters such as ;, |, `, $(, or && inside the username parameter

Detection Strategies

• Inspect web server and proxy logs for POST or GET requests to ELECOM management endpoints containing shell metacharacters in the username field
• Deploy network IDS signatures that flag HTTP parameters with command injection patterns directed at known ELECOM device IP ranges
• Correlate network telemetry to identify access points initiating outbound traffic that does not match expected firmware update or NTP destinations

Monitoring Recommendations

• Restrict and monitor administrative access to wireless infrastructure using a dedicated management VLAN
• Forward device syslog and authentication logs to a centralized SIEM for anomaly detection
• Alert on firmware version changes or configuration backups initiated from unexpected source addresses

How to Mitigate CVE-2026-42062

Immediate Actions Required

• Apply the firmware update referenced in the Elecom Security Update advisory as soon as it is available for your model
• Block external access to the device's web management interface at the network perimeter
• Audit affected devices for signs of compromise, including unauthorized accounts and modified configurations

Patch Information

ELECOM has published a security advisory listing affected models and the firmware versions that remediate CVE-2026-42062. Administrators should consult the Elecom Security Update and the JVN #03037325 Advisory to identify the correct firmware build for each deployed model and apply it through the device's standard update procedure.

Workarounds

• Disable remote management on the WAN interface and limit administrative access to trusted internal hosts only
• Place affected access points behind a firewall that filters HTTP and HTTPS traffic to the management interface
• Replace end-of-life ELECOM models that no longer receive firmware updates with currently supported hardware

# Example: restrict access to the device management interface using iptables
# Allow only an administrative subnet (10.0.0.0/24) to reach the device at 192.168.1.1
iptables -A FORWARD -s 10.0.0.0/24 -d 192.168.1.1 -p tcp --dport 80 -j ACCEPT
iptables -A FORWARD -s 10.0.0.0/24 -d 192.168.1.1 -p tcp --dport 443 -j ACCEPT
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP