CVE-2022-43108 is a critical stack overflow vulnerability identified in the Tenda AC23 router firmware version V16.03.07.45_cn. The vulnerability arises from improper handling of the 'firewallEn' parameter within the 'formSetFirewallCfg' function. Specifically, the stack overflow occurs when this parameter is processed, allowing an attacker to overwrite the stack memory. This type of vulnerability (classified under CWE-787: Out-of-bounds Write) can lead to arbitrary code execution, denial of service, or complete compromise of the affected device. The CVSS v3.1 base score of 9.8 reflects the severity, indicating that the vulnerability is remotely exploitable over the network without any authentication or user interaction. The impact includes full confidentiality, integrity, and availability compromise of the device. Given that Tenda AC23 is a consumer-grade Wi-Fi 6 router, exploitation could allow attackers to control network traffic, intercept sensitive data, or pivot into internal networks. No public exploits have been reported yet, and no patches have been linked, which suggests that affected users should be vigilant and seek firmware updates from the vendor. The vulnerability's network attack vector and lack of required privileges make it highly dangerous, especially in environments where these routers are deployed without additional network segmentation or protections.

For European organizations, the exploitation of this vulnerability could have significant consequences. Many small and medium enterprises (SMEs), as well as home offices, use consumer-grade routers like the Tenda AC23 due to their cost-effectiveness and performance. A successful attack could lead to unauthorized access to internal networks, interception of confidential communications, and disruption of business operations. Given the critical nature of the vulnerability, attackers could deploy malware, exfiltrate sensitive data, or create persistent backdoors. This is particularly concerning for sectors handling sensitive personal data under GDPR, as breaches could lead to regulatory penalties and reputational damage. Additionally, compromised routers could be leveraged as part of botnets or for launching further attacks within European networks. The lack of available patches increases the risk window, making proactive mitigation essential.

1. Immediate mitigation involves isolating the affected Tenda AC23 routers from critical network segments to limit potential lateral movement. 2. Monitor network traffic for unusual patterns indicative of exploitation attempts, such as unexpected firewall configuration changes or anomalous outbound connections. 3. Check with Tenda for firmware updates addressing this vulnerability and apply them promptly once available. 4. If firmware updates are not yet available, consider replacing affected devices with routers from vendors with timely security support. 5. Implement network segmentation and strict firewall rules to minimize exposure of router management interfaces to untrusted networks. 6. Disable remote management features on the router unless absolutely necessary, and if enabled, restrict access to trusted IP addresses only. 7. Employ intrusion detection/prevention systems (IDS/IPS) that can detect exploitation attempts targeting known stack overflow patterns. 8. Educate users and administrators about the risks of using consumer-grade routers in sensitive environments and encourage regular security assessments.