CVE-2026-101075: Netcore NR289-GE Router RCE Vulnerability

CVE-2026-101075 Overview

CVE-2026-101075 is an operating system command injection vulnerability affecting the Netcore NR289-GE router running firmware version 1.4.5102. The flaw resides in the system function invoked by the /location_time.cgi endpoint within the Location Time Handler component. Attackers can manipulate the mac argument to inject arbitrary shell commands that execute in the context of the router firmware. Remote exploitation is possible across the network without authentication or user interaction. Public disclosure of the exploit details has occurred, and the vendor did not respond to the researcher's disclosure attempts. The vulnerability maps to CWE-77: Improper Neutralization of Special Elements used in a Command.

Critical Impact

Unauthenticated remote attackers can execute arbitrary operating system commands on affected Netcore NR289-GE routers, enabling full device takeover and pivoting into connected networks.

Affected Products

• Netcore NR289-GE Router
• Firmware version 1.4.5102
• Location Time Handler component (/location_time.cgi)

Discovery Timeline

• 2026-09-28 - CVE CVE-2026-101075 published to NVD
• 2026-09-28 - Last updated in NVD database

Technical Details for CVE-2026-101075

Vulnerability Analysis

The vulnerability resides in the Location Time Handler of the Netcore NR289-GE router firmware. When a request reaches /location_time.cgi, the handler takes the attacker-controlled mac parameter and passes it directly into a system() call without sanitization or quoting. Because system() invokes a shell, any metacharacters embedded in mac are interpreted and executed as additional commands. Code injected this way runs with the privileges of the web server process on the router, which on embedded devices of this class is typically root. Successful exploitation yields full control of the router: configuration tampering, credential theft, DNS redirection, traffic interception, and lateral movement into the LAN.

Root Cause

The root cause is improper neutralization of special elements passed to an OS command [CWE-77]. The mac argument is concatenated into a shell command string without input validation, allowlisting, or safe-execution APIs such as execve() with argument arrays. The firmware trusts the structure of the incoming parameter, which a remote attacker fully controls.

Attack Vector

Exploitation requires only network reach to the router's HTTP management interface. An attacker sends a crafted request to /location_time.cgi where the mac parameter contains shell metacharacters such as ;, |, backticks, or $(...) followed by arbitrary commands. No credentials are required and no user interaction is involved. If the management interface is reachable from the WAN, exploitation is possible directly from the internet; on LAN-only configurations, an attacker on the local network or a hijacked internal host can trigger it.

Technical analysis of the request structure and parameter handling is documented in the public Netcore NR289-GE command injection write-up and the VulDB entry for CVE-2026-101075.

Detection Methods for CVE-2026-101075

Indicators of Compromise

• HTTP requests to /location_time.cgi where the mac parameter contains shell metacharacters such as ;, |, &, backticks, or $(...) sequences.
• Unexpected outbound connections originating from the router to attacker infrastructure following requests to the Location Time Handler.
• Unauthorized changes to router configuration, DNS settings, firewall rules, or administrative credentials.
• New or unknown processes spawned by the embedded web server on the device.

Detection Strategies

• Inspect HTTP and HTTPS traffic destined for the router management interface for anomalous mac parameter values that contain command separators or encoded shell syntax.
• Deploy network intrusion detection signatures that match requests to /location_time.cgi with non-MAC-address content in the mac field.
• Correlate router administrative requests with subsequent outbound traffic from the device to flag post-exploitation callbacks.

Monitoring Recommendations

• Centralize router and gateway logs for review of CGI access patterns and configuration changes.
• Alert on any inbound WAN-side requests reaching the device management interface.
• Baseline normal DNS resolver, firmware, and routing configuration, and alert on deviations.

How to Mitigate CVE-2026-101075

Immediate Actions Required

• Restrict access to the router's HTTP management interface to trusted management VLANs or hosts only, and disable WAN-side administration.
• Replace affected Netcore NR289-GE devices in high-value or internet-exposed deployments until a vendor fix is available.
• Rotate administrative credentials and audit router configuration, DNS, and firewall rules for unauthorized changes.
• Place the device behind an upstream firewall that blocks unsolicited inbound traffic to management ports.

Patch Information

No vendor patch is available at the time of publication. According to the public disclosure, the vendor was contacted but did not respond. Monitor the VulDB vulnerability record #410946 and the vendor's support channels for any future firmware updates addressing the Location Time Handler.

Workarounds

• Disable remote management on the WAN interface and limit LAN-side access to a dedicated administrative subnet.
• Use network segmentation to isolate the affected router from sensitive hosts and services.
• Apply upstream web application firewall or IDS rules that drop requests to /location_time.cgi containing shell metacharacters in the mac parameter.
• Consider decommissioning the device in favor of a supported platform if the vendor continues not to issue a fix.

# Example upstream iptables rule to block external access to the router's HTTP management port
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -i <wan_iface> -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -i <wan_iface> -j DROP