CVE-2026-0403 identifies a security vulnerability in the NETGEAR Orbi RBR750 router, classified under CWE-20 (Improper Input Validation). The vulnerability allows attackers who are connected to the router's local area network (LAN) and possess high privileges to inject operating system commands due to insufficient validation of input data. This flaw could enable an attacker to execute arbitrary commands on the router's underlying operating system, potentially leading to unauthorized control or disruption of the device. The vulnerability does not require user interaction and has no known exploits in the wild as of the publication date. The CVSS 4.0 vector indicates that the attack vector is adjacent (AV:A), attack complexity is low (AC:L), no privileges are required (PR:H), no user interaction is needed (UI:N), and the impact on confidentiality, integrity, and availability is limited or low. The affected product version is listed as '0', which likely indicates initial or unspecified firmware versions. The vulnerability was published on January 13, 2026, and is currently in a published state without available patches. The root cause is improper input validation, which is a common software weakness that can lead to command injection if untrusted input is executed without proper sanitization. This vulnerability is particularly concerning for environments where the router is accessible by multiple users on the LAN, as it could be exploited by malicious insiders or compromised devices within the network.

For European organizations, the impact of CVE-2026-0403 is generally low due to the requirement for high privileges and LAN access, limiting remote exploitation. However, in environments where the NETGEAR RBR750 router is deployed in shared or less controlled LAN segments, attackers with network access could leverage this vulnerability to execute arbitrary commands, potentially leading to device compromise, network disruption, or lateral movement within the network. This could affect confidentiality and integrity of network traffic and device configurations. Critical infrastructure or enterprises relying on these routers for network connectivity might experience operational disruptions if exploited. The absence of known exploits reduces immediate risk, but the vulnerability could be leveraged in targeted attacks or insider threat scenarios. Organizations with weak internal network segmentation or insufficient access controls are at higher risk. The low CVSS score reflects limited impact scope, but the potential for escalation or pivoting attacks exists if combined with other vulnerabilities or misconfigurations.

1. Monitor NETGEAR advisories closely and apply firmware updates or patches as soon as they become available to address CVE-2026-0403. 2. Restrict LAN access to the router’s management interface by implementing strict network segmentation and access control lists (ACLs) to limit administrative access only to trusted personnel and devices. 3. Disable or restrict remote management features on the router to reduce exposure. 4. Employ network monitoring and intrusion detection systems to identify unusual command execution or administrative activity on the router. 5. Conduct regular audits of router configurations and user privileges to ensure no unauthorized access is possible. 6. Educate network administrators about the risks of improper input validation vulnerabilities and the importance of secure configuration management. 7. Consider deploying additional security layers such as network access control (NAC) to prevent unauthorized devices from connecting to the LAN. 8. If possible, isolate critical network segments from general LAN access to reduce the attack surface. 9. Implement strong authentication mechanisms and change default credentials on all network devices. 10. Prepare incident response plans to quickly address potential exploitation scenarios involving network infrastructure devices.