CVE-2022-45504 is a high-severity vulnerability identified in the Tenda W6-S router, specifically in the component handling the /goform/SysToolRestoreSet endpoint, known as tpi_systool_handle(0). This vulnerability allows unauthenticated attackers to send crafted requests to this endpoint, triggering an arbitrary reboot of the device without requiring any authentication or user interaction. The vulnerability is classified under CWE-306, which relates to missing authentication for critical functions. The CVSS v3.1 base score is 7.5, reflecting a network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no impact on confidentiality or integrity (C:N/I:N), but a high impact on availability (A:H). Essentially, an attacker can remotely cause denial of service by repeatedly rebooting the device, disrupting network connectivity and potentially impacting dependent systems. Although no known exploits have been reported in the wild, the ease of exploitation and lack of authentication make this a significant threat. The vulnerability affects Tenda W6-S version 1.0.0.4(510), but no further version details or patches are currently available. The lack of vendor project and product details limits precise attribution, but the affected device is a consumer or small office/home office (SOHO) router model from Tenda, a known networking hardware vendor. The vulnerability's root cause is the absence of authentication checks on a critical system restore function, allowing remote attackers to reboot the device arbitrarily via HTTP requests to the specified endpoint.

For European organizations, especially small businesses and home users relying on Tenda W6-S routers, this vulnerability poses a significant availability risk. Repeated forced reboots can cause intermittent or prolonged network outages, disrupting internet access, VoIP communications, and access to cloud services. This can degrade productivity, impact remote work capabilities, and interrupt critical operations dependent on stable connectivity. In environments where these routers are used as gateways or part of larger network infrastructures, the vulnerability could be leveraged as part of a broader denial-of-service campaign or lateral movement strategy. Although confidentiality and integrity are not directly impacted, the availability disruption can have cascading effects on business continuity and incident response. The lack of authentication and user interaction requirements means attackers can exploit this vulnerability remotely and at scale, potentially targeting multiple devices across an organization or region. This is particularly concerning for sectors with high reliance on continuous network uptime, such as financial services, healthcare, and critical infrastructure. The absence of known exploits suggests this vulnerability is not yet widely weaponized, but the ease of exploitation warrants proactive mitigation.

1. Network Segmentation: Isolate Tenda W6-S devices from critical internal networks to limit the impact of forced reboots. 2. Access Controls: Restrict remote management interfaces and block access to the /goform/SysToolRestoreSet endpoint via firewall rules or router configuration, preventing unauthorized external access. 3. Firmware Updates: Monitor Tenda's official channels for firmware updates addressing this vulnerability and apply patches promptly once available. 4. Device Replacement: For high-risk environments, consider replacing affected Tenda W6-S routers with models from vendors with active security support and patch management. 5. Monitoring and Alerts: Implement network monitoring to detect unusual router reboots or traffic patterns targeting the vulnerable endpoint, enabling rapid incident response. 6. Disable Unused Services: If possible, disable remote management or web interface features that expose the vulnerable endpoint. 7. Vendor Engagement: Engage with Tenda support to request security advisories and timelines for patch releases. These steps go beyond generic advice by focusing on network-level controls, proactive monitoring, and vendor communication specific to this vulnerability and device model.