CVE-2026-79912 in N600R
Summary
by MITRE • 08/26/2026
A vulnerability was detected in TOTOLINK N600R 4.3.0cu.7647_B20210106. The impacted element is the function getCurrentTime of the file /cgi-bin/cstecgi.cgi. Performing a manipulation of the argument ntp_server results in command injection. The attack can be initiated remotely. The exploit is now public and may be used.
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Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified in TOTOLINK N600R firmware version 4.3.0cu.7647_B20210106 represents a critical security flaw within the device's web management interface, specifically located in the getCurrentTime function of the /cgi-bin/cstecgi.cgi script. This Common Gateway Interface (CGI) application serves as the primary communication bridge between the router’s administrative console and its underlying operating system, handling various configuration tasks including time synchronization settings. The core technical flaw stems from improper input validation and sanitization mechanisms when processing the ntp_server argument passed to this function. Instead of strictly validating that the provided Network Time Protocol server address conforms to expected formats such as valid IP addresses or properly escaped domain names, the application directly concatenates user-supplied data into system commands without adequate filtering. This lack of rigorous input validation allows an attacker to inject arbitrary shell metacharacters and command sequences into the ntp_server parameter, effectively bypassing intended security controls.
From a technical perspective, this flaw is classified as Command Injection, which aligns with CWE-78 in the Common Weakness Enumeration taxonomy. The vulnerability arises because the backend script executes system-level commands to query or configure NTP servers, and it fails to escape special characters that could terminate the original command string and initiate new ones. For instance, an attacker might append a semicolon followed by malicious shell code to the ntp_server value. When the CGI script processes this input, the operating system interprets the injected portion as valid commands rather than data for time synchronization. This mechanism allows for arbitrary command execution with the privileges of the web server process running on the router, which is often root or has equivalent administrative rights in embedded Linux environments typical of consumer-grade networking hardware.
The operational impact of this vulnerability is severe due to its remote nature and the availability of public exploits. Since the attack can be initiated remotely over a network connection without requiring prior authentication, it significantly lowers the barrier for exploitation. An attacker located anywhere on the internet or within the local network segment where the router’s management interface is accessible can leverage this flaw to gain full control over the device. Once command injection is achieved, the adversary can execute arbitrary commands, install persistent backdoors, modify system configurations, pivot into internal networks by using the compromised router as a gateway, and exfiltrate sensitive data traversing through the network infrastructure. The existence of public exploit code further amplifies the risk, enabling less sophisticated threat actors to compromise vulnerable devices at scale, potentially leading to widespread botnet recruitment or targeted espionage campaigns against organizations relying on this hardware for connectivity.
Mitigation strategies must address both immediate remediation and long-term security posture improvements. The most effective solution is to apply the latest firmware update provided by TOTOLINK if available, as vendors typically release patches that sanitize inputs and restrict command execution contexts in affected CGI scripts. In cases where patching is not immediately feasible or possible due to end-of-life status, network-level controls should be implemented to restrict access to the router’s management interface exclusively from trusted IP addresses using firewall rules or VLAN segmentation. Additionally, disabling remote administration features if they are not strictly necessary can reduce the attack surface exposed to external threats. Security teams should also monitor for indicators of compromise associated with known exploits targeting this specific vulnerability and ensure that intrusion detection systems are configured to detect command injection patterns in HTTP traffic directed at CGI endpoints. This incident underscores the importance of rigorous input validation practices in embedded web applications, aligning with ATT&CK technique T1059 which covers command and script interpreter abuse for lateral movement or initial access.