CVE-2026-22550: WRC-X1500GS/GSA-B RCE Vulnerability

CVE-2026-22550 Overview

CVE-2026-22550 is an OS command injection vulnerability affecting ELECOM WRC-X1500GS-B and WRC-X1500GSA-B wireless routers. The vulnerability allows authenticated users to execute arbitrary operating system commands on the affected devices through specially crafted requests. This type of vulnerability (CWE-78) represents a significant security risk in network infrastructure devices, as successful exploitation could lead to complete device compromise.

Critical Impact

Authenticated attackers can execute arbitrary OS commands on vulnerable ELECOM routers, potentially leading to full device takeover, network compromise, and persistent access to the affected infrastructure.

Affected Products

• ELECOM WRC-X1500GS-B Wireless Router
• ELECOM WRC-X1500GSA-B Wireless Router

Discovery Timeline

• 2026-02-03 - CVE-2026-22550 published to NVD
• 2026-02-03 - Last updated in NVD database

Technical Details for CVE-2026-22550

Vulnerability Analysis

This command injection vulnerability exists in the web management interface of ELECOM WRC-X1500GS-B and WRC-X1500GSA-B wireless routers. The vulnerability is network-accessible with low attack complexity, though it requires authenticated access to the device's management interface. Once an attacker has valid credentials, they can craft malicious requests that inject operating system commands into vulnerable input fields or parameters that are passed directly to system shell functions without proper sanitization.

The impact of successful exploitation is severe, affecting the confidentiality, integrity, and availability of the targeted device. An attacker could potentially extract sensitive configuration data, modify router settings, establish persistent backdoor access, pivot to other devices on the network, or disrupt network services entirely.

Root Cause

The root cause of this vulnerability is improper neutralization of special elements used in an OS command (CWE-78). The affected routers fail to adequately sanitize user-supplied input before passing it to system-level command execution functions. This allows attackers to break out of the intended command context and inject additional commands that are executed with the privileges of the web server process, typically running as root on embedded devices.

Attack Vector

The attack vector is network-based, requiring the attacker to have authenticated access to the router's web management interface. Once authenticated, the attacker can submit crafted HTTP requests containing command injection payloads. These payloads exploit insufficient input validation in specific management functions, allowing shell metacharacters and command separators (such as ;, |, &&, or backticks) to be processed as part of system commands.

The vulnerability can be exploited by injecting OS commands through vulnerable parameters in the web interface. Command separators and shell metacharacters are used to append malicious commands to legitimate operations processed by the router. For detailed technical information, refer to the JVN #94012927 Advisory and the Elecom Security News Update.

Detection Methods for CVE-2026-22550

Indicators of Compromise

• Unusual outbound network connections from the router to external IP addresses
• Unexpected processes or services running on the router device
• Modified router configuration files or unauthorized administrative accounts
• Anomalous HTTP requests to the router's management interface containing shell metacharacters

Detection Strategies

• Monitor web server logs on the router for requests containing command injection patterns such as ;, |, &&, $(), or backtick characters
• Implement network-level monitoring to detect unusual traffic patterns from router management interfaces
• Deploy intrusion detection system (IDS) rules to identify command injection attempts targeting ELECOM devices
• Review authentication logs for unauthorized or suspicious login attempts to router management interfaces

Monitoring Recommendations

• Enable comprehensive logging on the router's web management interface if supported
• Implement SIEM correlation rules to detect multiple failed authentication attempts followed by successful logins
• Monitor for DNS queries or network connections from the router to known malicious infrastructure
• Regularly audit router configurations for unauthorized changes or new user accounts

How to Mitigate CVE-2026-22550

Immediate Actions Required

• Update affected ELECOM WRC-X1500GS-B and WRC-X1500GSA-B routers to the latest firmware version immediately
• Restrict access to the router's web management interface to trusted IP addresses only
• Change default credentials and use strong, unique passwords for router administration
• Disable remote management access if not required for operations
• Segment network management interfaces from general user traffic

Patch Information

ELECOM has released security updates to address this vulnerability. Administrators should consult the official Elecom Security News Update for specific firmware versions and download links. It is critical to apply the security patch as soon as possible to remediate this command injection vulnerability.

Workarounds

• Implement network access control lists (ACLs) to restrict management interface access to specific trusted IP addresses
• Place the router management interface behind a VPN to add an additional authentication layer
• Disable the web management interface entirely if command-line or console management is feasible
• Monitor and log all access attempts to the router management interface for anomaly detection

# Example: Restrict management access via firewall rules
# Block external access to router management port (example using iptables)
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP