CVE-2025-6487 is a critical stack-based buffer overflow vulnerability identified in the TOTOLINK A3002R router, specifically version 1.1.1-B20200824.0128. The flaw resides in the formRoute function within the /boafrm/formRoute file. This function improperly handles the 'subnet' argument, allowing an attacker to manipulate this input to trigger a stack-based buffer overflow. Such a vulnerability can be exploited remotely without requiring user interaction, and only limited privileges (PR:L) are needed, indicating that an attacker with some level of access could launch the attack over the network. The vulnerability has a CVSS 4.0 base score of 8.7 (high severity), reflecting its potential to severely impact confidentiality, integrity, and availability. The vector indicates 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). The exploit has been publicly disclosed, increasing the risk of exploitation, although no confirmed exploits in the wild have been reported yet. The vulnerability's nature as a stack-based buffer overflow means that successful exploitation could lead to arbitrary code execution, potentially allowing attackers to take full control of the affected device, disrupt network operations, or pivot into internal networks. Given the critical role of routers in network infrastructure, this vulnerability poses a significant threat to any organization using the affected TOTOLINK A3002R firmware version.

For European organizations, the exploitation of CVE-2025-6487 could have severe consequences. Compromised routers can serve as entry points for attackers to infiltrate corporate networks, leading to data breaches, espionage, or disruption of services. The ability to execute arbitrary code remotely on a network device undermines the confidentiality, integrity, and availability of network communications. This could result in interception or manipulation of sensitive data, network downtime, or use of the compromised device as a launchpad for further attacks within the organization or against third parties. Critical sectors such as finance, healthcare, government, and telecommunications are particularly at risk due to their reliance on secure and stable network infrastructure. Additionally, the public disclosure of the exploit increases the likelihood of automated attacks targeting vulnerable devices, raising the urgency for mitigation. The impact extends beyond individual organizations to potentially affect national critical infrastructure and cross-border communications within Europe.

1. Immediate firmware update: Organizations should verify if their TOTOLINK A3002R devices are running the vulnerable firmware version 1.1.1-B20200824.0128 and upgrade to the latest patched firmware as soon as it becomes available from TOTOLINK. 2. Network segmentation: Isolate vulnerable devices from critical network segments to limit potential lateral movement if exploitation occurs. 3. Access control: Restrict management interfaces of the router to trusted IP addresses and disable remote management if not required. 4. Intrusion detection: Deploy network intrusion detection systems (NIDS) with signatures or heuristics capable of detecting exploitation attempts targeting the formRoute function or anomalous subnet parameter usage. 5. Monitor logs: Continuously monitor router logs and network traffic for unusual patterns indicative of exploitation attempts. 6. Replace legacy devices: Consider phasing out TOTOLINK A3002R devices in favor of more secure and actively maintained hardware, especially in high-security environments. 7. Vendor engagement: Engage with TOTOLINK support channels to obtain official patches and security advisories. 8. Incident response readiness: Prepare incident response plans specifically addressing potential router compromise scenarios to enable rapid containment and remediation.