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 HTTP POST request handler component, within the setDiagnosisCfg function of the /cgi-bin/cstecgi.cgi file. The vulnerability arises from improper sanitization or validation of the 'ip' argument passed to this function, allowing an attacker to inject arbitrary commands. Since the vulnerability can be exploited remotely without requiring user interaction or authentication, an attacker can send crafted HTTP POST requests to the affected endpoint to execute arbitrary system commands on the device. This can lead to unauthorized control over the router, potentially enabling attackers to manipulate network traffic, deploy malware, or pivot into internal networks. The CVSS 4.0 base score is 5.3, indicating a medium severity level, reflecting the ease of remote exploitation but limited scope of impact due to the requirement of low privileges (PR:L) and limited confidentiality, integrity, and availability impacts. No public exploits are currently known to be in the wild, but the exploit details have been disclosed publicly, increasing the risk of future exploitation. The vulnerability affects a specific firmware version of the TOTOLINK T6 router, a device commonly used in small office and home office environments.

For European organizations, this vulnerability poses a significant risk primarily to small and medium-sized enterprises (SMEs) and home office users relying on TOTOLINK T6 routers. Successful exploitation could allow attackers to gain control over network infrastructure, leading to interception or redirection of sensitive data, disruption of internet connectivity, or use of compromised routers as a foothold for further attacks within corporate networks. Given the remote and unauthenticated nature of the exploit, attackers could target vulnerable devices en masse, potentially resulting in widespread network outages or data breaches. The impact is heightened in sectors with critical reliance on network availability and confidentiality, such as finance, healthcare, and government agencies operating remotely or with distributed offices. Additionally, compromised routers could be enlisted into botnets, amplifying the threat landscape for European networks.

To mitigate this vulnerability, affected organizations should prioritize upgrading the TOTOLINK T6 firmware to a patched version once released by the vendor. In the absence of an official patch, network administrators should implement strict network segmentation to isolate vulnerable devices from critical infrastructure. Deploying web application firewalls (WAFs) or intrusion prevention systems (IPS) capable of detecting and blocking malicious HTTP POST requests targeting /cgi-bin/cstecgi.cgi can reduce exposure. Disabling remote management features on the router or restricting access to trusted IP addresses can further limit attack vectors. Regularly monitoring network traffic for unusual patterns and conducting vulnerability scans to identify affected devices are recommended. Organizations should also educate users about the risks of using outdated firmware and encourage timely updates. Finally, maintaining robust incident response plans to quickly address potential compromises will help minimize damage.