CVE-2024-40415 is a critical security vulnerability identified in the Tenda AX1806 router firmware version 1.0.0.1. The vulnerability is a stack-based buffer overflow located in the /goform/SetStaticRouteCfg endpoint, specifically within the sub_519F4 function. Buffer overflows occur when a program writes more data to a buffer than it can hold, which can overwrite adjacent memory and lead to arbitrary code execution. In this case, the vulnerability allows an unauthenticated attacker to send specially crafted requests to the router’s HTTP interface, triggering the overflow. This can result in remote code execution (RCE) with the privileges of the router’s firmware process, potentially allowing full control over the device. The CVSS 3.1 base score of 9.8 reflects the vulnerability’s network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and high impact on confidentiality (C:H), integrity (I:H), and availability (A:H). The vulnerability is classified under CWE-120, which covers classic buffer overflow issues. No patches or fixes have been published yet, and no exploits are known in the wild, but the severity and ease of exploitation make this a critical threat for affected users.

The impact of CVE-2024-40415 is severe for organizations and individuals using Tenda AX1806 routers. Successful exploitation can lead to complete compromise of the router, allowing attackers to intercept, modify, or block network traffic, launch further attacks within the internal network, and potentially establish persistent backdoors. This undermines network confidentiality, integrity, and availability. For enterprises relying on these devices for branch or home office connectivity, this could lead to data breaches, disruption of business operations, and lateral movement into corporate networks. The lack of authentication and user interaction requirements means attackers can exploit this remotely and automatically, increasing the risk of widespread attacks. The absence of patches further exacerbates the threat, leaving devices exposed until mitigations or firmware updates are released.

Until an official patch is released, organizations should implement several specific mitigations: 1) Immediately isolate or replace Tenda AX1806 routers running vulnerable firmware, especially in critical network segments. 2) Restrict access to the router’s management interface by implementing network segmentation and firewall rules to block inbound traffic to the /goform/SetStaticRouteCfg endpoint from untrusted networks. 3) Disable remote management features if enabled, to reduce exposure. 4) Monitor network traffic for unusual HTTP requests targeting the vulnerable endpoint and set up intrusion detection/prevention systems (IDS/IPS) with custom signatures to detect exploitation attempts. 5) Engage with Tenda support channels to obtain firmware updates or advisories and apply patches promptly once available. 6) Educate users and administrators about the risk and encourage regular device inventory and firmware audits to identify vulnerable devices. 7) Consider deploying network-level protections such as web application firewalls (WAFs) that can block malformed requests targeting this vulnerability.