CVE-2025-28024 is a critical buffer overflow vulnerability identified in the TOTOLINK A810R router firmware version V4.1.2cu.5182_B20201026, specifically within the cstecgi.cgi component. Buffer overflow vulnerabilities occur when a program writes more data to a buffer than it can hold, potentially overwriting adjacent memory and leading to arbitrary code execution, system crashes, or privilege escalation. In this case, the vulnerability is remotely exploitable over the network (AV:N), requires no privileges (PR:N), and no user interaction (UI:N), making it highly accessible to attackers. The vulnerability affects confidentiality, integrity, and availability (C:H/I:H/A:H), indicating that successful exploitation could allow an attacker to fully compromise the device, execute arbitrary code, manipulate data, or cause denial of service. The vulnerability is classified under CWE-120, which corresponds to classic buffer overflow issues. Although no known exploits are currently reported in the wild, the high CVSS score of 9.8 reflects the severe risk posed by this flaw. The TOTOLINK A810R is a consumer and small office/home office (SOHO) router, and the vulnerable CGI script likely handles web-based management or configuration functions, which are typically exposed to local networks and sometimes to the internet if remote management is enabled. The absence of vendor or product details beyond the firmware version limits the scope of affected devices, but the critical nature of the vulnerability demands immediate attention. No patches or mitigation links are currently available, indicating that users and administrators must rely on interim protective measures until an official fix is released.

For European organizations, the impact of this vulnerability can be significant, especially for small businesses, home offices, and remote workers relying on TOTOLINK A810R routers. Exploitation could lead to full compromise of the router, allowing attackers to intercept, modify, or redirect network traffic, potentially exposing sensitive corporate data or enabling lateral movement into internal networks. The integrity of network communications could be undermined, and availability of internet connectivity could be disrupted, affecting business operations. Given the router’s role as a network gateway, attackers could establish persistent footholds or launch further attacks against connected systems. The vulnerability's ease of exploitation and lack of required authentication increase the risk of widespread attacks, particularly in environments where remote management is enabled or where devices are exposed to the internet. Additionally, the vulnerability could be leveraged in botnet campaigns or as part of multi-stage attacks targeting European critical infrastructure or enterprises, amplifying its potential impact.

1. Immediate network segmentation: Isolate TOTOLINK A810R devices from critical internal networks to limit potential lateral movement in case of compromise. 2. Disable remote management interfaces: Ensure that web-based management (especially cstecgi.cgi or similar CGI scripts) is accessible only from trusted local networks and not exposed to the internet. 3. Implement strict firewall rules: Block inbound traffic to the router’s management ports from untrusted sources. 4. Monitor network traffic for anomalies: Use IDS/IPS solutions to detect unusual activity targeting the router’s CGI endpoints or signs of exploitation attempts. 5. Regularly audit device firmware versions: Identify all TOTOLINK A810R devices in the environment and verify firmware versions to assess exposure. 6. Engage with TOTOLINK support channels: Request information on patches or firmware updates addressing this vulnerability and apply them promptly once available. 7. Employ network-level protections: Use VPNs and encrypted tunnels for remote access to reduce exposure of management interfaces. 8. Educate users and administrators about the risks of enabling remote management and encourage best practices in router configuration.