CVE-2026-1547 identifies a command injection vulnerability in the Totolink A7000R router firmware version 4.1cu.4154. The vulnerability resides in the setUnloadUserData function of the /cgi-bin/cstecgi.cgi endpoint, where the plugin_name parameter is improperly sanitized. This allows an attacker to inject arbitrary OS commands remotely without requiring authentication or user interaction. The vulnerability is exploitable over the network, making it a significant risk for exposed devices. Command injection vulnerabilities can lead to full system compromise, enabling attackers to execute arbitrary commands with the privileges of the affected process, potentially leading to data theft, device manipulation, or network pivoting. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no authentication required (AT:N), no user interaction (UI:N), and low impact on confidentiality, integrity, and availability (VC:L, VI:L, VA:L). Although the impact metrics are low, the ability to execute arbitrary commands remotely elevates the threat. No official patches or updates have been published yet, and public exploit code is available, increasing the risk of exploitation. Organizations using this router model should consider immediate mitigation steps to reduce exposure.

For European organizations, this vulnerability poses a risk of unauthorized remote command execution on affected Totolink A7000R routers, potentially leading to network compromise, data interception, or disruption of services. Given that routers are critical network infrastructure components, exploitation could allow attackers to intercept or manipulate traffic, launch further attacks within internal networks, or disrupt connectivity. The medium CVSS score reflects moderate impact, but the ease of exploitation without authentication increases risk. Organizations in sectors such as telecommunications, finance, government, and critical infrastructure that rely on Totolink devices could face operational disruptions and data breaches. The lack of patches means that vulnerable devices remain exposed, and public exploit availability may lead to increased attack attempts. The threat is particularly relevant for small and medium enterprises and home office environments where Totolink routers are more commonly deployed and may lack rigorous security monitoring.

1. Immediately isolate affected Totolink A7000R routers from untrusted networks, especially the internet, to prevent remote exploitation. 2. Implement network segmentation to limit access to router management interfaces only to trusted internal hosts. 3. Disable remote management features on the router if not required, reducing the attack surface. 4. Monitor network traffic for unusual activity or command injection attempts targeting /cgi-bin/cstecgi.cgi endpoints. 5. Employ intrusion detection/prevention systems (IDS/IPS) with signatures for known exploit patterns related to this vulnerability. 6. Regularly audit and update router firmware; coordinate with Totolink for forthcoming patches or advisories. 7. Consider replacing vulnerable devices with models from vendors with active security support if patches are delayed. 8. Educate network administrators on the risks of command injection and ensure strong access controls on network devices. 9. Maintain backups of router configurations to enable rapid recovery if compromise occurs. 10. Engage with cybersecurity incident response teams to prepare for potential exploitation scenarios.