CVE-2026-76862 in NR255-V
Summary
by MITRE • 09/16/2026
Netcore NR255-V version 1.5.130703 contains an os command argument injection vulnerability in the Nettools tcpdump launch paths, including ntools_start_set_cgi, ntools_tcpdump_start_set_cgi, exe_default, and ntools_proc components. Attackers can inject crafted arguments into these tcpdump launch routines to manipulate executed system commands on the device.
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Analysis
by VulDB Data Team • 09/16/2026
The vulnerability identified in Netcore NR255-V version 1.5.130703 represents a critical security flaw within the network diagnostic utilities embedded in the router firmware. Specifically, this is an operating system command injection vulnerability located in the launch paths for tcpdump, a widely used packet analyzer tool often included in networking devices for troubleshooting connectivity issues. The affected components include ntools_start_set_cgi, ntools_tcpdump_start_set_cgi, exe_default, and ntools_proc. These modules are responsible for initiating network capture processes based on user input or configuration parameters provided through the device's management interface.
The technical root cause of this vulnerability lies in improper validation and sanitization of arguments passed to system command execution functions. When a user submits data intended to configure tcpdump parameters, such as interface selection or filtering criteria, the application fails to adequately escape special characters that have meaning to the operating system shell. This allows an attacker to inject additional commands by appending them to legitimate input strings. For instance, if the underlying code constructs a command line using string concatenation without proper quoting or escaping of user-supplied data, an adversary can terminate the intended argument and append arbitrary shell commands like semicolons, pipes, or backticks followed by malicious payloads.
From an operational perspective, this vulnerability poses a severe risk to the integrity and confidentiality of the network infrastructure. Since tcpdump typically runs with elevated privileges necessary for capturing raw network packets on interfaces, successful exploitation could allow an attacker to execute arbitrary system commands with those same high-level permissions. This effectively results in full remote code execution on the device without requiring authentication if the vulnerable CGI endpoints are accessible over the network. An adversary could leverage this access to install persistent backdoors, exfiltrate sensitive traffic data including credentials and proprietary information, pivot into internal networks by manipulating routing tables or firewall rules, or disrupt service availability by terminating critical system processes.
This flaw aligns with Common Weakness Enumeration identifier CWE-78, which covers Improper Neutralization of Special Elements used in an OS Command commonly known as OS Command Injection. The attack vector typically involves interacting with the web-based management interface of the router, making it exploitable remotely over HTTP or HTTPS if the administrative panel is exposed to untrusted networks. In terms of MITRE ATT&CK framework classification, this vulnerability facilitates initial access and privilege escalation techniques where an attacker leverages command injection to gain control over the underlying operating system environment, potentially leading to lateral movement within a local network segment.
Mitigation strategies for this vulnerability primarily involve applying vendor-provided firmware updates that patch the input validation logic in the specified components. Administrators should ensure their Netcore NR255-V devices are running patched versions where argument sanitization is strictly enforced before passing data to system calls. In cases where immediate patching is not feasible, network segmentation can help limit exposure by restricting access to the management interface only from trusted administrative subnets. Additionally, disabling unnecessary diagnostic tools like tcpdump if they are not actively required for operational support reduces the attack surface available to potential adversaries seeking to exploit these command execution pathways.