CVE-2025-69763 identifies a critical security vulnerability in the Tenda AX3 router firmware version 16.03.12.11. The flaw is a stack-based buffer overflow located in the formSetIptv function, specifically triggered by the vlanId parameter. This vulnerability arises due to improper bounds checking, which allows an attacker to overwrite memory on the stack. Exploitation can lead to memory corruption, enabling remote code execution (RCE) without requiring any authentication or user interaction. The vulnerability is remotely exploitable over the network, meaning attackers can target vulnerable devices directly if they are reachable. The CVSS v3.1 base score of 9.8 reflects the critical nature of this vulnerability, with attack vector being network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). The vulnerability is classified under CWE-121 (Stack-based Buffer Overflow), a common and dangerous software weakness. Currently, no patches or firmware updates have been published to address this issue, and no known exploits have been reported in the wild. However, the potential for exploitation is significant given the severity and ease of attack. The vulnerability primarily affects Tenda AX3 routers running the specified firmware version, which are commonly used in home and small office environments but may also be present in enterprise edge networks. Attackers exploiting this vulnerability could gain full control over the device, intercept or manipulate network traffic, or use the compromised router as a foothold for further attacks within the network.

For European organizations, this vulnerability poses a severe risk to network security and operational continuity. Compromise of Tenda AX3 routers could lead to unauthorized access to internal networks, interception of sensitive data, and disruption of internet connectivity. Critical infrastructure and enterprises relying on these devices for network edge routing or IPTV services could face significant confidentiality breaches, data integrity issues, and denial of service conditions. The ability to execute code remotely without authentication increases the likelihood of widespread exploitation, especially in environments where routers are exposed to the internet or insufficiently segmented. This could facilitate lateral movement by attackers, enabling further compromise of corporate networks or critical services. Additionally, the lack of available patches means organizations must rely on network-level mitigations and monitoring to reduce risk. The potential impact extends to privacy violations, regulatory non-compliance (e.g., GDPR), and financial losses due to service outages or data breaches.

1. Immediately restrict external network access to Tenda AX3 router management interfaces by implementing firewall rules or network segmentation to prevent unauthorized remote connections. 2. Disable the IPTV functionality or the vulnerable formSetIptv feature if it is not required, reducing the attack surface. 3. Monitor network traffic for unusual activity or signs of exploitation attempts targeting the vlanId parameter or related router services. 4. Employ intrusion detection/prevention systems (IDS/IPS) with updated signatures to detect exploitation attempts once available. 5. Maintain strict access controls and change default credentials to prevent unauthorized local or remote access. 6. Regularly audit network devices to identify and inventory Tenda AX3 routers and verify firmware versions. 7. Prepare to deploy firmware updates or patches as soon as they become available from the vendor. 8. Consider temporary replacement or isolation of vulnerable devices in critical network segments until remediation is possible. 9. Educate network administrators about this vulnerability and encourage vigilance for related security advisories. 10. Collaborate with vendors and security communities to obtain timely updates and share threat intelligence.