CVE-2026-35506: ELECOM Wireless LAN Access Point RCE Flaw

CVE-2026-35506 Overview

CVE-2026-35506 is an OS command injection vulnerability [CWE-78] affecting ELECOM wireless LAN access point devices. The flaw resides in the processing of the ping_ip_addr parameter exposed by the device's management interface. An authenticated attacker who sends a crafted request can execute arbitrary operating system commands on the underlying device. Successful exploitation impacts the confidentiality, integrity, and availability of the access point. The issue is tracked by JPCERT/CC under advisory JVN03037325 and was disclosed alongside an ELECOM security update announcement.

Critical Impact

An authenticated remote attacker can execute arbitrary OS commands on affected ELECOM wireless LAN access points, gaining full control of the device and the network segment it serves.

Affected Products

• ELECOM wireless LAN access point devices (specific models listed in JVN03037325)
• Devices using vulnerable firmware versions referenced in the ELECOM advisory
• Management interfaces exposing the ping_ip_addr diagnostic parameter

Discovery Timeline

• 2026-05-13 - CVE-2026-35506 published to NVD
• 2026-05-13 - Last updated in NVD database

Technical Details for CVE-2026-35506

Vulnerability Analysis

The vulnerability is an OS command injection flaw classified under [CWE-78]. ELECOM access point firmware exposes a diagnostic ping function that accepts a user-supplied IP address through the ping_ip_addr parameter. The firmware passes this parameter to an underlying shell or system call without adequate sanitization or argument separation. An attacker authenticated to the device's web management interface can append shell metacharacters to the parameter value and execute arbitrary commands in the context of the device process, typically running with elevated privileges on embedded Linux.

Because access points commonly run management services as root, command execution generally yields full device compromise. Attackers can extract Wi-Fi credentials, modify routing rules, pivot into internal networks, or install persistent firmware implants.

Root Cause

The root cause is the construction of an OS command string using untrusted input from the ping_ip_addr HTTP parameter. The firmware concatenates this input into a ping command invocation without validating that the value is a well-formed IP address or escaping shell metacharacters such as ;, |, &, and backticks.

Attack Vector

The attack vector is network-based and requires high privileges, meaning the attacker must hold valid administrative credentials for the device's management interface. User interaction is not required. After authenticating, the attacker submits a crafted HTTP request to the diagnostic endpoint containing shell metacharacters in the ping_ip_addr field. The injected commands run on the device immediately.

The vulnerability manifests when the firmware invokes a shell to run ping with the attacker-supplied address. By appending a command separator followed by an arbitrary command, the attacker breaks out of the intended ping invocation. See JVN Security Advisory JVN03037325 for vendor-supplied technical details.

Detection Methods for CVE-2026-35506

Indicators of Compromise

• HTTP POST or GET requests to the device management interface containing shell metacharacters (;, |, &, `, $()) within the ping_ip_addr parameter.
• Unexpected outbound connections originating from the access point to attacker-controlled infrastructure.
• New or modified files in writable firmware locations such as /tmp or /var on the device, including unexpected scripts or binaries.
• Administrator account activity from unfamiliar source IP addresses immediately preceding anomalous device behavior.

Detection Strategies

• Inspect web traffic to access point management URLs for ping_ip_addr values that do not conform to a strict IPv4 or IPv6 syntax.
• Correlate authentication events on the device with subsequent diagnostic endpoint usage to flag short post-login command bursts.
• Monitor DNS queries and outbound flows from network infrastructure devices, which should rarely initiate external connections.

Monitoring Recommendations

• Forward access point syslog and HTTP access logs to a centralized log platform for retention and analysis.
• Alert on changes to administrative credentials, firmware versions, or configuration files on ELECOM devices.
• Baseline normal management interface usage and alert on deviations such as off-hours logins or rapid sequential diagnostic requests.

How to Mitigate CVE-2026-35506

Immediate Actions Required

• Apply the firmware update published by ELECOM in the Elecom Security Update Announcement as soon as it is available for your model.
• Restrict access to the device management interface to trusted administrative VLANs or management hosts only.
• Rotate administrative credentials on all ELECOM access points and disable any unused or default accounts.
• Audit authentication logs for unexpected administrator logins that could indicate prior exploitation.

Patch Information

ELECOM has released firmware updates addressing CVE-2026-35506. Refer to the Elecom Security Update Announcement and JVN Security Advisory JVN03037325 for the list of affected models and corresponding fixed firmware versions. Apply the vendor-supplied firmware on every affected device.

Workarounds

• Disable remote management on the WAN interface so the diagnostic endpoint is unreachable from untrusted networks.
• Place access points behind a management firewall that only permits administrative traffic from designated jump hosts.
• Enforce strong, unique administrator passwords and, where supported, multi-factor authentication on management portals.

# Configuration example: restrict management access at the network edge
# Allow administrative access only from the management subnet 10.10.0.0/24
iptables -A INPUT -p tcp -s 10.10.0.0/24 --dport 80  -j ACCEPT
iptables -A INPUT -p tcp -s 10.10.0.0/24 --dport 443 -j ACCEPT
iptables -A INPUT -p tcp --dport 80  -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP