CVE-2025-63460 is a stack-based buffer overflow vulnerability identified in the Totolink A7000R router firmware version 9.1.0u.6115_B20201022. The vulnerability arises from improper bounds checking in the sub_4222E0 function when processing the ssid5g parameter, which is related to the configuration of the 5 GHz wireless SSID. An attacker can craft a specially malformed request containing an oversized or malformed ssid5g parameter, causing the function to overwrite the stack memory. This leads to a denial of service by crashing the router, disrupting network availability. The vulnerability is remotely exploitable without any authentication or user interaction, increasing the attack surface significantly. The CVSS v3.1 base score is 7.5 (high), reflecting the network vector, low attack complexity, no privileges required, no user interaction, and impact limited to availability. While no exploits are currently known in the wild and no patches have been released, the vulnerability represents a critical risk to network stability. The CWE-121 classification confirms this is a classic stack-based buffer overflow issue, which could potentially be leveraged for more severe attacks if combined with other vulnerabilities, though currently only DoS impact is confirmed.

For European organizations, the primary impact of CVE-2025-63460 is the disruption of network availability due to denial of service on affected Totolink A7000R routers. This can lead to loss of connectivity for business operations, impacting productivity and potentially critical services relying on stable network infrastructure. Given that the vulnerability can be exploited remotely without authentication, attackers can cause widespread outages or targeted disruptions. This is particularly concerning for small and medium enterprises or branch offices that may rely on consumer-grade or SOHO routers like the Totolink A7000R. The lack of patches increases the risk window. While confidentiality and integrity are not directly affected, the availability impact can indirectly affect business continuity and incident response capabilities. Organizations in sectors such as finance, healthcare, and critical infrastructure that depend on reliable network access may face operational and reputational damage if exploited.

1. Immediately restrict external network access to the management interfaces of Totolink A7000R routers, especially blocking access to the 5 GHz SSID configuration endpoints. 2. Implement network segmentation to isolate vulnerable routers from critical internal networks and sensitive systems. 3. Monitor network traffic for unusual or malformed requests targeting the ssid5g parameter or related wireless configuration endpoints. 4. Where possible, replace or upgrade affected Totolink A7000R devices with models from vendors providing timely security updates. 5. Apply strict firewall rules to limit inbound traffic to trusted sources only. 6. Engage with Totolink support or vendor channels to obtain firmware updates or patches once available. 7. Conduct regular vulnerability scans and penetration tests focusing on network infrastructure devices to detect exploitation attempts. 8. Educate IT staff on recognizing signs of router crashes or network outages caused by potential exploitation of this vulnerability.