CVE-2025-63460 is a stack overflow vulnerability identified in the Totolink A7000R router firmware version 9.1.0u.6115_B20201022. The vulnerability arises from improper handling of the ssid5g parameter within the sub_4222E0 function, where a crafted input can overflow the stack memory. This overflow can cause the device to crash or reboot, resulting in a Denial of Service (DoS) condition. The vulnerability can be triggered remotely by sending a specially crafted request to the affected router without requiring authentication or user interaction, making it relatively easy to exploit. Although no public exploits have been reported yet, the flaw poses a significant risk to network availability. The affected firmware version is specific, and no patch links are currently available, indicating that vendors or users should monitor for updates. The vulnerability impacts the confidentiality and integrity minimally but severely affects availability by disrupting network connectivity. The attack surface includes any exposed management or configuration interfaces that process the ssid5g parameter. This vulnerability highlights the importance of secure input validation and memory management in embedded device firmware.

For European organizations, this vulnerability could lead to temporary loss of network connectivity or degraded wireless service due to router crashes. This disruption can affect business operations, especially for organizations relying on Totolink A7000R routers in critical network segments or remote offices. The DoS condition could be exploited by attackers to cause repeated outages, potentially as part of a larger attack campaign or to distract from other malicious activities. The impact is more pronounced in sectors with high dependency on stable wireless infrastructure, such as small and medium enterprises, educational institutions, and public services. Although the vulnerability does not directly expose sensitive data, the resulting downtime can lead to productivity losses and increased operational costs. Additionally, if attackers combine this DoS with other attack vectors, it could facilitate further compromise. The lack of a patch at the time of disclosure increases the urgency for mitigation measures.

1. Immediately restrict access to the router's management interfaces, especially from untrusted networks, using firewall rules or network segmentation. 2. Disable remote management features if not required to reduce exposure. 3. Monitor network traffic for unusual or malformed requests targeting the ssid5g parameter or related wireless configuration endpoints. 4. Implement network-level protections such as intrusion detection/prevention systems (IDS/IPS) that can detect and block exploit attempts targeting this vulnerability. 5. Regularly check for firmware updates from Totolink and apply patches promptly once available. 6. Consider replacing affected devices with models from vendors with stronger security track records if patches are delayed. 7. Educate network administrators on the signs of DoS attacks and establish incident response procedures to quickly recover from outages. 8. Use network redundancy and failover mechanisms to minimize service disruption in case of router failure.