CVE-2026-101076 Overview
CVE-2026-101076 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 /set_ntp_server_ip.cgi endpoint within the CGI Handler component. An unauthenticated remote attacker can manipulate the ntp_ip parameter to inject arbitrary shell commands that execute with the privileges of the web service. A public proof-of-concept has been released, and the vendor did not respond to disclosure attempts.
Critical Impact
Unauthenticated remote attackers can execute arbitrary operating system commands on affected Netcore NR289-GE routers, enabling full device takeover, traffic interception, and pivoting into connected networks.
Affected Products
- Netcore NR289-GE router, firmware version 1.4.5102
- Component: CGI Handler (/set_ntp_server_ip.cgi)
- Vulnerable parameter: ntp_ip
Discovery Timeline
- 2026-09-28 - CVE-2026-101076 published to the National Vulnerability Database (NVD)
- 2026-09-28 - Last updated in NVD database
- 2026-09-29 - EPSS score published at 2.011% (80.09 percentile)
Technical Details for CVE-2026-101076
Vulnerability Analysis
The vulnerability is classified as [CWE-77: Improper Neutralization of Special Elements used in a Command]. The /set_ntp_server_ip.cgi handler accepts a user-supplied ntp_ip value and passes it directly to a system() call without sanitization or validation. Because the CGI endpoint is reachable over the network and does not require authentication, any attacker able to reach the router's management interface can trigger command execution.
Successful exploitation grants the attacker shell access with the privileges of the CGI process, which on consumer routers typically runs as root. This enables persistent firmware modification, DNS hijacking, credential theft, and lateral movement into the LAN.
Root Cause
The root cause is the absence of input validation on the ntp_ip HTTP parameter before concatenation into a shell command. Shell metacharacters such as ;, |, &&, and backticks are not filtered, allowing arbitrary command chaining within the invocation of the NTP configuration routine.
Attack Vector
The attack vector is network-based with no authentication or user interaction required. An attacker sends a crafted HTTP request to /set_ntp_server_ip.cgi with a malicious ntp_ip value containing shell metacharacters. The injected payload executes on the device when the CGI handler processes the request. A public exploit is documented in the GitHub PoC for NTP Injection and detailed on the VulDB CVE-2026-101076 Detail page.
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Stop Exploit AttemptsDetection Methods for CVE-2026-101076
Indicators of Compromise
- HTTP POST or GET requests to /set_ntp_server_ip.cgi containing shell metacharacters (;, |, &, `, $()) in the ntp_ip parameter.
- Unexpected outbound connections from the router to attacker-controlled infrastructure shortly after NTP configuration requests.
- Modified NTP configuration files or new persistence artifacts in router firmware storage.
- Unusual DNS resolver or routing table changes on the affected device.
Detection Strategies
- Inspect web server and CGI access logs for requests to /set_ntp_server_ip.cgi that include non-IP characters in the ntp_ip field.
- Deploy network intrusion detection signatures that flag HTTP requests to the vulnerable endpoint containing shell metacharacters.
- Monitor router management interfaces for anomalous administrative traffic originating from untrusted network segments.
Monitoring Recommendations
- Capture and retain router administrative traffic for retroactive analysis if compromise is suspected.
- Alert on new or unexpected processes launched by the HTTP daemon on devices where host telemetry is available.
- Baseline outbound traffic from network infrastructure devices to detect command-and-control activity.
How to Mitigate CVE-2026-101076
Immediate Actions Required
- Restrict access to the router's web management interface to trusted internal networks only, and disable WAN-side administration.
- Place affected NR289-GE devices behind a firewall that blocks inbound requests to /set_ntp_server_ip.cgi from untrusted sources.
- Audit routers for signs of compromise, including modified configurations, unknown accounts, and unexpected outbound connections.
- Plan replacement of unsupported Netcore NR289-GE hardware given the vendor's lack of response to disclosure.
Patch Information
No vendor patch is available. According to the disclosure, the vendor was contacted early but did not respond. Operators should treat the device as end-of-support for security purposes and prioritize migration to a supported platform. Refer to VulDB Vulnerability #410947 for ongoing tracking.
Workarounds
- Disable remote management entirely and limit the web UI to a dedicated management VLAN.
- Enforce access control lists on upstream firewalls to block external access to router administrative ports (typically TCP/80 and TCP/443).
- Segment the router from sensitive internal assets so that a compromised device cannot pivot into critical systems.
- Replace the device with vendor-supported hardware that receives security updates.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
