CVE-2025-7524 is a command injection vulnerability identified in the TOTOLINK T6 router, specifically in version 4.1.5cu.748_B20211015. The flaw resides in the setDiagnosisCfg function within the /cgi-bin/cstecgi.cgi HTTP POST request handler. An attacker can manipulate the 'ip' argument sent to this function to inject arbitrary commands that the device executes. Since the vulnerability is exploitable remotely without requiring user interaction or prior authentication, it presents a significant risk. The vulnerability allows an attacker to execute arbitrary system commands on the affected device, potentially leading to full device compromise, unauthorized access to the internal network, or use of the device as a pivot point for further attacks. The CVSS 4.0 base score is 5.3 (medium severity), reflecting the ease of remote exploitation but limited scope and impact on confidentiality, integrity, and availability. No patches or mitigations have been officially published yet, and while no exploits are currently known to be in the wild, public disclosure of the exploit code increases the risk of exploitation by malicious actors. The vulnerability affects a widely used consumer-grade router model, which is often deployed in home and small office environments, potentially exposing many users to risk if devices remain unpatched or unmitigated.

For European organizations, the impact of this vulnerability can be significant, especially for small businesses and remote workers relying on TOTOLINK T6 routers for internet connectivity. Successful exploitation could allow attackers to gain control over the router, intercept or manipulate network traffic, and potentially access internal corporate resources. This could lead to data breaches, disruption of business operations, and lateral movement within the network. Additionally, compromised routers could be enlisted into botnets or used to launch further attacks, amplifying the threat landscape. Given the medium CVSS score, the impact on large enterprises may be limited if they do not use this specific router model or have robust network segmentation and monitoring. However, the risk remains for less protected environments and consumer-grade deployments within European countries.

1. Immediate mitigation should include isolating affected TOTOLINK T6 routers from critical network segments to limit potential lateral movement. 2. Network administrators should monitor network traffic for unusual patterns or unexpected command execution attempts targeting the /cgi-bin/cstecgi.cgi endpoint. 3. Implement strict firewall rules to restrict remote access to router management interfaces, ideally limiting access to trusted IP addresses only. 4. Disable remote management features if not required. 5. Regularly audit and inventory network devices to identify any TOTOLINK T6 routers running the vulnerable firmware version. 6. Since no official patch is currently available, consider replacing vulnerable devices with models from vendors with timely security updates. 7. Employ network intrusion detection/prevention systems (IDS/IPS) with signatures tuned to detect exploitation attempts targeting this vulnerability. 8. Educate users about the risks of using outdated firmware and the importance of applying updates promptly once available.