CVE-2026-1329 is a stack-based buffer overflow vulnerability identified in the Tenda AX1803 router firmware version 1.0.0.1. The vulnerability resides in the fromGetWifiGuestBasic function, which processes parameters related to guest Wi-Fi settings via the /goform/WifiGuestSet endpoint. By crafting malicious input values for parameters such as guestWrlPwd, guestEn, guestSsid, hideSsid, and guestSecurity, an attacker can overflow a stack buffer, potentially overwriting the return address or other control data on the stack. This can lead to arbitrary code execution with elevated privileges on the device. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, making it highly accessible to attackers. The CVSS v4.0 score of 8.7 reflects the critical nature of the flaw, with network attack vector, low attack complexity, no privileges or user interaction needed, and high impact on confidentiality, integrity, and availability. Although no active exploitation has been reported, a public exploit is available, increasing the urgency for mitigation. The affected device is commonly used in residential and small business environments, where compromised routers can serve as entry points for lateral movement, data interception, or launching further attacks within corporate networks. The lack of vendor patches at the time of disclosure necessitates immediate defensive measures to reduce exposure.

For European organizations, the exploitation of CVE-2026-1329 could result in full compromise of affected Tenda AX1803 routers, enabling attackers to execute arbitrary code and potentially gain control over network traffic. This can lead to interception of sensitive communications, unauthorized access to internal resources, and use of compromised devices as pivot points for broader network intrusion. Small and medium enterprises (SMEs) and home offices relying on this router model are particularly at risk due to typically weaker network segmentation and security monitoring. The disruption or manipulation of guest Wi-Fi settings could also degrade network availability or facilitate further attacks against connected devices. Given the remote exploitability and lack of authentication requirements, attackers can launch attacks from anywhere, increasing the threat surface. The potential impact extends to critical infrastructure sectors if these routers are deployed in such environments, affecting data confidentiality, integrity, and service availability.

1. Immediately check for and apply any firmware updates or patches released by Tenda addressing CVE-2026-1329. 2. If no patch is available, restrict access to the router's management interfaces and the /goform/WifiGuestSet endpoint by implementing network-level controls such as firewall rules or access control lists (ACLs) to limit exposure to trusted IP addresses only. 3. Disable guest Wi-Fi functionality if not required, or isolate guest networks using VLANs or separate subnets to minimize impact if exploited. 4. Monitor network traffic for unusual activity targeting the vulnerable endpoint or signs of exploitation attempts, including anomalous requests to /goform/WifiGuestSet. 5. Replace affected devices with models from vendors with timely security update practices if patching is not feasible. 6. Educate users and administrators about the risks of using outdated router firmware and the importance of regular updates. 7. Employ network intrusion detection/prevention systems (IDS/IPS) with signatures for known exploit attempts targeting this vulnerability.