CVE-2026-61376: ELECOM Router Command Injection Flaw

CVE-2026-61376 Overview

CVE-2026-61376 is an OS Command Injection vulnerability [CWE-78] affecting ELECOM wireless LAN routers and access points. The flaw resides in the Restore Settings functionality. An authenticated attacker who can log in to the affected product can execute arbitrary operating system commands on the underlying device. Successful exploitation allows an attacker to take control of network infrastructure, pivot into internal networks, and intercept or manipulate traffic passing through the router.

Critical Impact
Authenticated attackers can execute arbitrary OS commands through the Restore Settings feature, leading to full compromise of ELECOM wireless LAN routers and access points.

Affected Products

ELECOM wireless LAN routers (specific models listed in the vendor advisory)
ELECOM wireless LAN access points (specific models listed in the vendor advisory)
Refer to the Elecom Security News Release for the complete list of impacted firmware versions

Discovery Timeline

2026-07-28 - CVE-2026-61376 published to NVD
2026-07-28 - Last updated in NVD database

Technical Details for CVE-2026-61376

Vulnerability Analysis

The vulnerability is classified as OS Command Injection [CWE-78]. It affects the Restore Settings feature exposed by the administrative interface of ELECOM wireless LAN routers and access points. The Restore Settings feature accepts a configuration file or parameters from an authenticated user. Insufficient sanitization allows attacker-controlled input to be passed to an operating system shell.

An attacker with administrative login access can inject shell metacharacters into the restore workflow. The injected commands execute in the context of the router's underlying operating system. The attack vector is network-based, and no user interaction is required beyond the attacker's own authenticated session.

Command execution on a wireless router provides persistence on the perimeter of the target network. Attackers can modify DNS settings, install backdoors in firmware, or capture credentials from clients associating with the access point. The EPSS score is 1.129% with a percentile of 63.14, indicating measurable interest in similar embedded device flaws.

Root Cause

The root cause is improper neutralization of special elements in input passed to the Restore Settings handler. The handler concatenates user-supplied data into an OS command string without escaping shell metacharacters. This design allows shell interpretation of characters such as ;, |, &, and backticks in fields that should be treated as data.

Attack Vector

An attacker must first authenticate to the router's management interface with high privileges. This is typically the administrator account required to access the Restore Settings page. Once authenticated, the attacker crafts a malicious configuration payload or manipulates request parameters submitted to the restore endpoint. The injected commands run with the privileges of the web management process, typically root on embedded router firmware.

Detailed technical exploitation steps have not been published. See the JVN Security Advisory for coordinated disclosure details.

Detection Methods for CVE-2026-61376

Indicators of Compromise

Unexpected administrative logins to the ELECOM device management interface from unusual source IP addresses
HTTP POST requests to the Restore Settings endpoint containing shell metacharacters such as ;, |, &, or backticks in configuration fields
Unauthorized changes to DNS server settings, firewall rules, or firmware on the affected device
Outbound connections from the router to unknown external hosts following administrative activity

Detection Strategies

Monitor management interface access logs for successful logins outside expected administrative windows and source ranges
Inspect HTTP request bodies to the restore configuration endpoint for shell metacharacters or encoded command sequences
Compare device configuration snapshots against a known-good baseline to identify unauthorized modifications
Correlate router login events with subsequent anomalous outbound traffic patterns from the device

Monitoring Recommendations

Forward router syslog and administrative audit logs to a centralized SIEM for retention and correlation
Alert on any use of the Restore Settings feature outside of change-management windows
Track DNS query patterns from clients on the wireless network to identify redirection to attacker-controlled resolvers
Baseline firmware hashes and periodically validate them against vendor-published values

How to Mitigate CVE-2026-61376

Immediate Actions Required

Apply the firmware update published by ELECOM as soon as it is available for the affected model
Restrict management interface access to trusted administrative networks using access control lists
Rotate all administrative credentials on affected devices and enforce strong, unique passwords
Disable remote administration over WAN interfaces unless strictly required for operations

Patch Information

ELECOM has released firmware updates addressing this vulnerability. Refer to the Elecom Security News Release and the JVN Security Advisory for the list of fixed firmware versions and download instructions. Apply the update through the device's firmware upgrade function following vendor guidance.

Workarounds

Limit access to the device management interface to a dedicated management VLAN or trusted IP ranges
Disable remote WAN-side management access until firmware updates are applied
Monitor administrative sessions and enforce session timeouts on the management console
Segment wireless client networks from the router's management plane where the hardware supports it

bash

# Example: restrict management access to a trusted subnet via upstream firewall
iptables -A FORWARD -p tcp -d <router-mgmt-ip> --dport 443 -s 10.10.0.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d <router-mgmt-ip> --dport 443 -j DROP