CVE-2026-7548 in NR1800X
Summary
by MITRE • 05/01/2026
A vulnerability was detected in Totolink NR1800X 9.1.0u.6279_B20210910. This affects the function sub_41A68C of the file /cgi-bin/cstecgi.cgi. Performing a manipulation of the argument setUssd results in command injection. The attack is possible to be carried out remotely. The exploit is now public and may be used.
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Analysis
by VulDB Data Team • 06/13/2026
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 management functionality. This issue resides in the sub_41A68C function of the /cgi-bin/cstecgi.cgi file, which processes user input through the setUssd parameter without adequate sanitization or validation mechanisms. The vulnerability stems from insufficient input filtering that allows malicious actors to inject arbitrary commands directly into the system's command execution pipeline, potentially enabling complete system compromise.
The technical implementation of this flaw demonstrates a classic command injection vulnerability where user-supplied data flows directly into system commands without proper escaping or encoding. The setUssd parameter in the cgi-bin interface accepts input that gets processed through a vulnerable function, creating a pathway for attackers to execute arbitrary shell commands on the affected device. This vulnerability operates at the application layer and leverages improper input validation practices that violate established security principles. The flaw falls under CWE-77 and CWE-78 categories, representing command injection vulnerabilities that can be exploited to execute system commands with the privileges of the web server process.
Remote exploitation capabilities significantly amplify the threat posed by this vulnerability, as attackers can leverage the issue from external network positions without requiring physical access to the device. The public availability of exploit code further compounds the risk, making it accessible to malicious actors who may not possess advanced technical skills. Successful exploitation could enable attackers to gain full administrative control over the router, potentially allowing them to modify network configurations, establish persistent backdoors, intercept network traffic, or use the device as a launching point for attacks against other networked systems. The impact extends beyond individual device compromise to potential network-wide consequences, as routers often serve as critical gateway points in network infrastructures.
The operational implications of this vulnerability are severe for organizations and individuals relying on Totolink NR1800X devices, particularly in environments where network security is paramount. Network administrators must immediately implement mitigations including firmware updates from the vendor, network segmentation to isolate affected devices, and monitoring for suspicious network activity. The vulnerability demonstrates the importance of input validation and proper sanitization in web applications, aligning with ATT&CK framework techniques related to command execution and privilege escalation. Organizations should also consider implementing intrusion detection systems to monitor for exploitation attempts and establish incident response procedures to address potential compromises. Given the public exploit availability, immediate remediation efforts are essential to prevent widespread exploitation across affected deployments.