CVE-2022-45520 is a high-severity stack overflow vulnerability identified in the Tenda W30E router firmware version V1.0.1.25(633). The vulnerability arises from improper handling of the 'page' parameter in the /goform/qossetting endpoint. Specifically, the stack overflow occurs when an attacker sends a specially crafted request with a maliciously long or malformed 'page' parameter, causing the router's software to overwrite parts of the stack memory. This type of vulnerability (CWE-787) can lead to denial of service (DoS) conditions by crashing the device or potentially enable remote code execution if exploited further, although no such exploits are currently known in the wild. The CVSS 3.1 base score of 7.5 reflects a high severity, primarily due to the vulnerability's network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction needed (UI:N). The impact is limited to availability (A:H), with no direct confidentiality or integrity impact reported. The vulnerability affects the router's QoS (Quality of Service) settings interface, which is typically accessible remotely or locally depending on device configuration. No official patch or vendor project information is currently available, and the affected versions are not explicitly detailed beyond the known firmware version. Given the nature of the vulnerability, exploitation could disrupt network connectivity or device stability, impacting users relying on these routers for internet access and network management.

For European organizations, the impact of this vulnerability can be significant, especially for small to medium enterprises (SMEs) and home office environments that commonly use consumer-grade routers like the Tenda W30E. A successful exploit could lead to denial of service, causing network outages and loss of internet connectivity, which in turn disrupts business operations, remote work, and communication. While the vulnerability does not directly compromise data confidentiality or integrity, the availability impact can indirectly affect business continuity and productivity. Additionally, if attackers leverage this vulnerability as a foothold, it could facilitate further attacks within the network. Organizations relying on Tenda W30E devices without proper segmentation or monitoring may face increased risk. The absence of known exploits in the wild reduces immediate threat but does not eliminate the risk, especially as attackers often develop exploits after vulnerabilities are publicly disclosed.

1. Immediate mitigation should involve isolating Tenda W30E devices from untrusted networks, especially restricting remote management access to trusted IPs or disabling it entirely if not needed. 2. Network administrators should implement strict firewall rules to block unauthorized access to the /goform/qossetting endpoint. 3. Monitor network traffic for unusual requests targeting the QoS settings interface, focusing on anomalous or oversized 'page' parameter values. 4. Where possible, replace affected Tenda W30E routers with devices from vendors that provide timely security updates and have a proven security track record. 5. If replacement is not feasible, consider deploying network-level intrusion prevention systems (IPS) capable of detecting and blocking stack overflow exploit attempts. 6. Regularly review and update router firmware; although no patch is currently available, stay alert for vendor advisories or community-developed fixes. 7. Implement network segmentation to limit the impact of compromised devices and prevent lateral movement within the network. 8. Educate users and administrators about the risks of exposing router management interfaces to the internet and enforce strong authentication policies where applicable.