CVE-2025-6149 is a critical buffer overflow vulnerability identified in the TOTOLINK A3002R router, specifically version 4.0.0-B20230531.1404. The flaw exists in the HTTP POST request handler component, within an unspecified function related to the /boafrm/formSysLog endpoint. The vulnerability arises from improper handling of the 'submit-url' argument, which can be manipulated by an attacker to cause a buffer overflow. This type of vulnerability typically allows an attacker to overwrite adjacent memory, potentially leading to arbitrary code execution, denial of service, or system compromise. The vulnerability is remotely exploitable without requiring user interaction or authentication, increasing its risk profile. The CVSS 4.0 base score is 8.7, indicating a high severity level, with network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. Although no public exploits are currently known to be in the wild, the exploit code has been disclosed publicly, which raises the likelihood of imminent exploitation attempts. The vulnerability affects a specific firmware version of the TOTOLINK A3002R, a consumer-grade router commonly used in home and small office environments. The lack of available patches at the time of disclosure further exacerbates the risk.

For European organizations, the impact of this vulnerability can be significant, especially for small and medium enterprises (SMEs) and home office users relying on TOTOLINK A3002R routers. Successful exploitation could allow attackers to gain unauthorized remote control over the router, enabling interception or manipulation of network traffic, deployment of malware, or pivoting to internal networks. This could lead to data breaches, disruption of business operations, and compromise of sensitive information. Given the router’s role as a network gateway, the integrity and availability of network services could be severely affected. Additionally, compromised routers could be leveraged as part of botnets for large-scale attacks, further amplifying the threat landscape. The vulnerability’s remote exploitability without authentication makes it particularly dangerous in environments where these devices are exposed to the internet or poorly segmented networks. European organizations with limited IT security resources may be disproportionately affected due to delayed patching or lack of awareness.

1. Immediate network segmentation: Isolate TOTOLINK A3002R devices from critical infrastructure and sensitive data networks to limit potential lateral movement in case of compromise. 2. Restrict remote management access: Disable or tightly control remote HTTP access to the router’s management interface, ideally limiting it to trusted IP addresses or VPN connections. 3. Monitor network traffic: Deploy intrusion detection/prevention systems (IDS/IPS) to detect anomalous POST requests targeting /boafrm/formSysLog or unusual traffic patterns indicative of exploitation attempts. 4. Firmware update vigilance: Regularly check TOTOLINK’s official channels for security patches addressing this vulnerability and apply updates promptly once available. 5. Temporary mitigations: If patching is not immediately possible, consider firewall rules to block or rate-limit HTTP POST requests to the vulnerable endpoint. 6. Incident response readiness: Prepare to isolate and remediate affected devices quickly if exploitation is detected, including factory resets and reconfiguration. 7. User awareness: Educate users about the risks of exposing router management interfaces and encourage secure configuration practices.