CVE-2025-5608 is a critical buffer overflow vulnerability identified in the Tenda AC18 router, specifically affecting firmware version 15.03.05.05. The vulnerability resides in the function formsetreboottimer within the /goform/SetSysAutoRebbotCfg endpoint. This function processes the rebootTime argument, and improper handling of this input leads to a buffer overflow condition. Because the vulnerability can be triggered remotely without authentication or user interaction, an attacker can exploit this flaw over the network by sending a specially crafted request to the vulnerable endpoint. The buffer overflow could allow an attacker to execute arbitrary code on the device, potentially leading to full compromise of the router. This could enable attackers to manipulate network traffic, intercept sensitive data, or use the device as a foothold for further attacks within the network. The CVSS v4.0 score is 8.7 (high severity), reflecting the vulnerability's network attack vector, low complexity, no required privileges or user interaction, and high impact on confidentiality, integrity, and availability. Although no public exploit is currently known to be actively used in the wild, the exploit code has been disclosed publicly, increasing the risk of imminent exploitation. No official patches or mitigations have been linked yet, which heightens the urgency for affected users to take protective measures.

For European organizations, the impact of this vulnerability could be significant, especially for those relying on Tenda AC18 routers in their network infrastructure. Compromise of these routers could lead to interception or manipulation of sensitive communications, disruption of network availability, and unauthorized access to internal systems. Given the router's role as a gateway device, attackers could pivot from the compromised router to other critical assets within the organization. This is particularly concerning for sectors with stringent data protection requirements such as finance, healthcare, and government entities in Europe. Additionally, the lack of authentication and user interaction requirements lowers the barrier for attackers, increasing the likelihood of exploitation. The public disclosure of exploit code further elevates the threat level, potentially leading to widespread attacks if mitigations are not promptly applied. Organizations could face operational disruptions, data breaches, and regulatory penalties under GDPR if sensitive personal data is exposed due to this vulnerability.

1. Immediate mitigation should include isolating or segmenting networks where Tenda AC18 routers are deployed to limit exposure. 2. Disable or restrict access to the /goform/SetSysAutoRebbotCfg endpoint if possible, for example by firewall rules or router configuration, to prevent remote exploitation. 3. Monitor network traffic for unusual requests targeting the rebootTime parameter or the vulnerable endpoint. 4. Implement network-level intrusion detection/prevention systems (IDS/IPS) with signatures tuned to detect exploitation attempts of this vulnerability. 5. Regularly audit and inventory network devices to identify all instances of Tenda AC18 routers and verify their firmware versions. 6. Engage with Tenda support channels to obtain official patches or firmware updates as soon as they become available. 7. Until patches are released, consider replacing vulnerable devices with alternative hardware from vendors with active security support. 8. Educate IT staff about this vulnerability and ensure incident response plans include steps for router compromise scenarios.