CVE-2022-44367 is a critical buffer overflow vulnerability identified in the Tenda i21 router firmware version V1.0.0.14(4656). The vulnerability exists in the handling of requests to the /goform/setUplinkInfo endpoint. Specifically, the flaw arises due to improper bounds checking when processing input data, which allows an attacker to overflow a buffer. This can lead to arbitrary code execution, denial of service, or system compromise. The vulnerability is remotely exploitable over the network without requiring any authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The impact on confidentiality, integrity, and availability is high, as an attacker can gain control over the device, intercept or manipulate traffic, or disrupt network connectivity. Although no public exploits have been reported in the wild to date, the high CVSS score of 9.8 underscores the severity and potential for exploitation. The vulnerability is classified under CWE-787 (Out-of-bounds Write), a common and dangerous class of memory corruption bugs. The lack of vendor or product information beyond the Tenda i21 model limits detailed attribution, but the affected device is a consumer-grade router, which is often deployed in both home and small office environments. The absence of an official patch link suggests that mitigation may currently rely on workarounds or firmware updates pending from the vendor. Given the nature of the vulnerability, attackers could leverage it to establish persistent footholds within affected networks or pivot to other internal systems.

For European organizations, the exploitation of this vulnerability in Tenda i21 routers could have significant consequences. Many small and medium enterprises (SMEs) and home offices use consumer-grade routers like the Tenda i21 due to their affordability and ease of deployment. A successful exploit could lead to full compromise of the router, enabling attackers to intercept sensitive communications, inject malicious traffic, or disrupt internet connectivity. This could result in data breaches, loss of business continuity, and exposure to further attacks such as lateral movement within corporate networks. Critical sectors relying on these devices for remote or branch connectivity—such as finance, healthcare, and manufacturing—may face increased risk. Additionally, compromised routers can be recruited into botnets, amplifying the threat landscape. The lack of authentication and user interaction requirements lowers the barrier for attackers, increasing the likelihood of automated exploitation attempts. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the potential for future attacks, especially as proof-of-concept code may emerge. Overall, the vulnerability poses a high risk to confidentiality, integrity, and availability of network infrastructure within European organizations using affected devices.

1. Immediate Network Segmentation: Isolate Tenda i21 routers from critical internal networks to limit potential lateral movement if compromised. 2. Firmware Updates: Monitor Tenda’s official channels for firmware patches addressing this vulnerability and apply updates promptly once available. 3. Access Controls: Restrict access to the router’s management interfaces, especially the /goform/setUplinkInfo endpoint, by implementing firewall rules that limit inbound traffic to trusted IP addresses only. 4. Network Monitoring: Deploy intrusion detection/prevention systems (IDS/IPS) tuned to detect anomalous requests targeting the vulnerable endpoint or signs of buffer overflow exploitation attempts. 5. Device Replacement: For high-security environments, consider replacing Tenda i21 routers with devices from vendors with robust security track records and timely patch management. 6. Vendor Engagement: Engage with Tenda support to obtain information on patch timelines and request security advisories. 7. Incident Response Preparedness: Prepare to respond to potential exploitation by maintaining backups of router configurations and establishing procedures for rapid device reimaging or replacement. 8. User Awareness: Educate users about the risks of using consumer-grade routers in professional environments and encourage reporting of unusual network behavior.