CVE-2022-43025 is a critical stack overflow vulnerability identified in the Tenda TX3 router firmware version US_TX3V1.0br_V16.03.13.11_multi_TDE01. The vulnerability arises from improper handling of the 'startIp' parameter in the /goform/SetPptpServerCfg endpoint. Specifically, the stack overflow (CWE-787) occurs when the input to this parameter exceeds the expected buffer size, allowing an attacker to overwrite adjacent memory on the stack. This can lead to arbitrary code execution, denial of service, or system compromise. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The CVSS score of 9.8 reflects the critical nature of this flaw, with high impact on confidentiality, integrity, and availability. Although no known exploits are currently reported in the wild, the ease of exploitation and severity make this a significant threat. The lack of official patch links suggests that a fix may not yet be publicly available, increasing the urgency for mitigation. The vulnerability affects a specific Tenda router model and firmware version, which is commonly used in home and small office environments for internet connectivity and VPN services via PPTP server configuration.

For European organizations, this vulnerability poses a substantial risk, especially for small and medium enterprises (SMEs) and home office setups relying on Tenda TX3 routers. Successful exploitation could allow attackers to gain full control over the affected device, enabling interception or manipulation of network traffic, deployment of malware, or pivoting into internal networks. This compromises confidentiality by exposing sensitive data, integrity by allowing unauthorized changes, and availability by potentially causing device crashes or network outages. Given the critical CVSS score and remote exploitability without authentication, attackers could target vulnerable devices en masse, leading to widespread disruption. Additionally, compromised routers could be leveraged as part of botnets or for launching further attacks against European infrastructure. The lack of patches and public exploits means organizations must proactively identify and mitigate this risk to prevent potential exploitation.

1. Immediate identification of Tenda TX3 routers running the vulnerable firmware version is essential. Network asset inventories should be updated to include device firmware details. 2. If possible, upgrade the router firmware to a version that addresses this vulnerability once available from Tenda. In the absence of an official patch, consider contacting Tenda support for guidance or firmware updates. 3. As a temporary measure, restrict access to the router's management interface and the /goform/SetPptpServerCfg endpoint by implementing network segmentation and firewall rules to limit exposure to trusted IP addresses only. 4. Disable the PPTP server feature if it is not required, as this directly mitigates the attack vector. 5. Monitor network traffic for unusual activity that could indicate exploitation attempts, such as unexpected requests to the vulnerable endpoint or anomalous router behavior. 6. Educate users and administrators about the risks and encourage prompt reporting of any suspicious device behavior. 7. Consider replacing vulnerable devices with models from vendors with timely security update practices if patching is not feasible.