CVE-2025-6129 is a critical buffer overflow vulnerability identified in the TOTOLINK EX1200T router, specifically version 4.1.2cu.5232_B20210713. The flaw resides in the HTTP POST request handler component, within the /boafrm/formSaveConfig endpoint. An attacker can exploit this vulnerability by manipulating the 'submit-url' argument in the POST request, causing a buffer overflow condition. This type of vulnerability can lead to arbitrary code execution, denial of service, or system compromise. The vulnerability is remotely exploitable without requiring user interaction or prior authentication, significantly increasing the attack surface. The CVSS 4.0 base score is 8.7, reflecting high severity, with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:L), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (VC:H/VI:H/VA:H). Although no public exploits have been observed in the wild yet, the exploit details have been disclosed publicly, raising the risk of imminent exploitation. The absence of patches or mitigation updates from the vendor at the time of publication further exacerbates the threat. Given the router's role in managing network traffic and security, successful exploitation could allow attackers to gain control over the device, intercept or manipulate network traffic, or pivot into internal networks, posing significant risks to affected organizations.

For European organizations, the exploitation of CVE-2025-6129 could have severe consequences. TOTOLINK EX1200T routers are commonly used in small to medium-sized enterprises and residential environments, often serving as primary network gateways. A compromised router can lead to full network compromise, enabling attackers to intercept sensitive communications, inject malicious payloads, or disrupt network availability. This can result in data breaches, intellectual property theft, operational downtime, and erosion of customer trust. Critical infrastructure sectors relying on these devices for connectivity could face cascading effects impacting service delivery. Additionally, since the vulnerability requires no authentication or user interaction, attackers can launch automated mass scanning and exploitation campaigns, increasing the likelihood of widespread impact. The lack of vendor patches means organizations must rely on alternative mitigations, increasing operational complexity and risk exposure. The high confidentiality, integrity, and availability impacts underscore the potential for significant damage to organizational assets and reputation.

1. Immediate network segmentation: Isolate TOTOLINK EX1200T devices from critical network segments to limit potential lateral movement if compromised. 2. Deploy Web Application Firewalls (WAFs) or Intrusion Prevention Systems (IPS) with custom rules to detect and block malicious POST requests targeting /boafrm/formSaveConfig, specifically those manipulating the 'submit-url' parameter. 3. Restrict remote management access to the router by disabling WAN-side administration or limiting it to trusted IP addresses via firewall rules. 4. Monitor network traffic for unusual patterns or spikes in POST requests to the vulnerable endpoint, leveraging SIEM solutions for alerting. 5. Engage with TOTOLINK support channels to obtain firmware updates or patches as soon as they become available; if unavailable, consider replacing vulnerable devices with alternatives from vendors with timely security support. 6. Implement network-level anomaly detection to identify potential exploitation attempts. 7. Educate IT staff on the vulnerability specifics to enhance incident response readiness. 8. Regularly audit and update router configurations to minimize exposure, including disabling unnecessary services and enforcing strong administrative credentials.