CVE-2025-59365 is a stack-based buffer overflow vulnerability classified under CWE-121, discovered in specific ASUS router firmware versions (3.0.0.4_386, 3.0.0.4_388, and 3.0.0.6_102). This vulnerability arises from improper handling of input data in the router's software, allowing an authenticated attacker to send a crafted request that overflows a stack buffer. The overflow can corrupt memory, leading to potential denial of service conditions by crashing or destabilizing the device. The attack vector is network-based (AV:N), requiring no user interaction (UI:N), but does require high privileges (PR:H), indicating that the attacker must have authenticated access to the device’s administrative interface or equivalent. The vulnerability impacts availability (VA:H) but does not affect confidentiality or integrity. The CVSS 4.0 base score is 6.9, reflecting a medium severity level. No public exploits are known at this time, but the vulnerability poses a risk to network stability and uptime. ASUS has acknowledged the issue and recommends monitoring their security advisories for firmware updates. The vulnerability is particularly concerning for environments where these routers serve as critical network gateways or infrastructure components.

For European organizations, exploitation of this vulnerability could lead to denial of service on affected ASUS routers, disrupting network connectivity and business operations. This is especially critical for enterprises and service providers relying on these routers for internet access, VPN termination, or internal segmentation. The requirement for authenticated access limits the attack surface but does not eliminate risk, as insider threats or compromised credentials could enable exploitation. Disruptions could affect availability of services, potentially impacting sectors such as finance, healthcare, and government that depend on continuous network uptime. Additionally, the outage could cascade, affecting connected systems and users. Given the medium severity, the impact is significant but not catastrophic, emphasizing the need for timely patching and access controls.

1. Apply firmware updates from ASUS as soon as they are released to address CVE-2025-59365. 2. Restrict administrative access to the routers by implementing network segmentation and limiting management interfaces to trusted IP addresses or VPN connections. 3. Enforce strong authentication mechanisms, including multi-factor authentication, to reduce the risk of credential compromise. 4. Monitor router logs and network traffic for unusual or unauthorized access attempts indicative of exploitation attempts. 5. Regularly audit and rotate administrative credentials to minimize insider threat risks. 6. Consider deploying intrusion detection/prevention systems (IDS/IPS) capable of identifying anomalous requests targeting router management interfaces. 7. Maintain an inventory of all ASUS routers in use, including firmware versions, to prioritize patching efforts. 8. Educate network administrators about this vulnerability and the importance of applying security updates promptly.