CVE-2022-40103 is a medium severity vulnerability identified in the Tenda i9 router firmware version 1.0.0.8(3828). The issue is a buffer overflow in the formSetAutoPing function. Buffer overflow vulnerabilities occur when a program writes more data to a buffer than it can hold, potentially overwriting adjacent memory. In this case, the vulnerability can be triggered by sending a specially crafted string to the affected function, causing the device to crash or become unresponsive, resulting in a Denial of Service (DoS) condition. The vulnerability does not affect confidentiality or integrity directly, but it impacts availability by disrupting normal device operation. The CVSS 3.1 base score is 5.5, reflecting a medium severity with the vector AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H, meaning the attack requires local access, low attack complexity, no privileges, user interaction is required, and the impact is limited to availability. No known exploits are currently reported in the wild, and no patches or vendor advisories have been published yet. The vulnerability is classified under CWE-787 (Out-of-bounds Write), a common class of memory corruption bugs that can lead to crashes or potentially more severe exploitation if combined with other vulnerabilities. Since the affected product is a consumer-grade router, exploitation would require an attacker to have local network access or trick a user into triggering the vulnerability via user interaction, limiting the attack surface somewhat but still posing a risk in environments where the device is deployed.

For European organizations, the primary impact of CVE-2022-40103 is the potential disruption of network connectivity and availability caused by a Denial of Service on Tenda i9 routers. This could affect small to medium enterprises or home office setups that rely on these routers for internet access and internal networking. The DoS could interrupt business operations, cause loss of productivity, and require manual intervention to restore service. While the vulnerability does not allow data theft or device takeover directly, the loss of availability can have cascading effects, especially in organizations with limited IT support or those using these routers in critical network segments. Additionally, if attackers combine this vulnerability with other exploits, there could be a risk of more severe compromise. The requirement for local access or user interaction reduces the risk of widespread remote exploitation but does not eliminate it, especially in environments with weak network segmentation or where social engineering could be used to induce user action.

To mitigate CVE-2022-40103, organizations should first identify any Tenda i9 routers running firmware version 1.0.0.8(3828) within their network. Since no official patches are currently available, the following steps are recommended: 1) Limit local network access to the router’s management interfaces by implementing strict network segmentation and access controls, ensuring only authorized personnel can interact with the device. 2) Disable or restrict any unnecessary services or remote management features that could be used to trigger the vulnerability. 3) Educate users about the risk of interacting with suspicious network prompts or links that could exploit user interaction requirements. 4) Monitor network traffic and device logs for unusual activity or repeated crashes that may indicate exploitation attempts. 5) Consider replacing affected devices with models from vendors that provide timely security updates and have a strong security track record. 6) Stay alert for vendor advisories or firmware updates addressing this vulnerability and apply them promptly once available.