CVE-2022-45671 is a high-severity buffer overflow vulnerability identified in the Tenda i22 router firmware version 1.0.0.3(4687). The vulnerability arises from improper handling of the 'appData' parameter within the 'formSetAppFilterRule' function. Specifically, this function fails to properly validate or limit the size of input data, leading to a classic stack-based buffer overflow (CWE-120). Exploiting this flaw requires no authentication or user interaction and can be triggered remotely over the network (AV:N), making it highly accessible to attackers. The vulnerability does not impact confidentiality or integrity directly but results in a complete denial of service (availability impact) by crashing or destabilizing the device. The CVSS 3.1 base score is 7.5 (high), reflecting the ease of exploitation and significant availability impact. No known public exploits or patches have been reported as of the published date (December 2, 2022). The Tenda i22 is a consumer-grade Wi-Fi 6 router, typically deployed in home and small office environments. The vulnerability could allow attackers to disrupt network connectivity by causing device reboots or crashes, potentially leading to extended downtime or network outages. Given the lack of authentication requirements, attackers can exploit this remotely without prior access, increasing the risk surface. The absence of patches or mitigations from the vendor at this time further elevates the threat level for affected devices still in use.

For European organizations, especially small businesses and home office users relying on Tenda i22 routers, this vulnerability poses a significant risk to network availability. Disruption of internet connectivity can lead to operational downtime, loss of productivity, and potential secondary impacts if critical services depend on these routers. While the vulnerability does not directly compromise data confidentiality or integrity, the denial of service can indirectly affect business continuity and service delivery. In sectors where continuous connectivity is critical (e.g., remote work, telemedicine, financial services), even short outages can have outsized consequences. Additionally, widespread exploitation could be leveraged as part of larger distributed denial-of-service (DDoS) campaigns or to create network instability. The lack of known exploits in the wild currently reduces immediate risk, but the ease of exploitation and absence of authentication requirements mean that threat actors could develop exploits rapidly. Organizations using Tenda i22 devices should consider the potential for targeted attacks or opportunistic scanning by attackers seeking vulnerable routers.

1. Immediate mitigation involves isolating Tenda i22 routers from untrusted networks or limiting their exposure to the internet, for example by disabling remote management features or applying strict firewall rules to restrict access to the router's management interfaces. 2. Network segmentation can reduce the impact of a compromised or crashed router by limiting affected devices and services. 3. Monitor network traffic and device logs for unusual activity or repeated crashes that may indicate exploitation attempts. 4. Engage with Tenda support channels to obtain firmware updates or patches addressing this vulnerability; if none are available, consider upgrading to alternative router models with active security support. 5. For organizations deploying these routers in critical environments, implement redundancy in network infrastructure to maintain connectivity in case of device failure. 6. Educate users about the risks of exposing router management interfaces and encourage secure configuration practices. 7. Employ network intrusion detection systems (NIDS) capable of detecting anomalous traffic patterns associated with exploitation attempts targeting buffer overflow vulnerabilities.