CVE-2026-1326 in NR1800X
Summary
by MITRE • 01/22/2026
A weakness has been identified in Totolink NR1800X 9.1.0u.6279_B20210910. This vulnerability affects the function setWanCfg of the file /cgi-bin/cstecgi.cgi of the component POST Request Handler. This manipulation of the argument Hostname causes command injection. The attack can be initiated remotely. The exploit has been made available to the public and could be used for attacks.
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Analysis
by VulDB Data Team • 01/30/2026
The vulnerability identified in Totolink NR1800X firmware version 9.1.0u.6279_B20210910 represents a critical command injection flaw within the device's web interface handling mechanism. This weakness resides in the setWanCfg function of the /cgi-bin/cstecgi.cgi component, specifically within the POST Request Handler module that processes administrative configuration requests. The vulnerability manifests when the Hostname parameter is manipulated during the WAN configuration process, allowing attackers to inject arbitrary commands that execute with elevated privileges on the affected device.
This command injection vulnerability stems from inadequate input validation and sanitization within the web application's request processing pipeline. The attack vector is particularly concerning as it operates entirely through remote exploitation via HTTP POST requests, eliminating the need for physical access or local network presence. The flaw falls under CWE-77 which specifically addresses command injection vulnerabilities where untrusted data is directly incorporated into command execution contexts without proper sanitization or encoding. The public availability of exploits for this vulnerability significantly increases the risk surface, as malicious actors can readily leverage this weakness for unauthorized system access and control.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise and potential network infiltration. An attacker who successfully exploits this vulnerability can gain root-level access to the router, enabling them to modify network configurations, establish persistent backdoors, monitor network traffic, and potentially use the device as a pivot point for attacking other systems within the local network. The attack surface is particularly dangerous given that many home and small office routers remain unpatched and accessible from the internet, creating a widespread attack vector that could affect thousands of devices simultaneously. This vulnerability aligns with ATT&CK technique T1059.001 for command and script interpreter execution, as well as T1071.004 for application layer protocol traffic shaping.
Mitigation strategies for this vulnerability must encompass both immediate remediation and long-term security enhancements. The most critical immediate action is to upgrade to the latest firmware version provided by Totolink, which should contain patches addressing the input validation gaps in the setWanCfg function. Network administrators should also implement network segmentation and access control measures to limit exposure, including firewall rules that restrict access to the router's administrative interfaces from untrusted networks. Additional protective measures include disabling unnecessary services, implementing strong authentication mechanisms, and regularly monitoring network traffic for suspicious activities that might indicate exploitation attempts. The vulnerability demonstrates the importance of input validation and the principle of least privilege in web application security, highlighting how a single parameter handling flaw can compromise entire network infrastructures. Organizations should also consider implementing intrusion detection systems specifically configured to identify patterns associated with command injection attacks targeting web application interfaces.