CVE-2026-2137 is a buffer overflow vulnerability identified in the Tenda TX3 router firmware up to version 16.03.13.11_multi. The vulnerability arises from improper input validation in a function associated with the /goform/SetIpMacBind endpoint. Specifically, manipulation of the argument list passed to this function can overflow a buffer, which may lead to arbitrary code execution. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, making it highly accessible to attackers. The CVSS 4.0 score of 8.7 reflects the high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges required. While the exact function affected is unspecified, the endpoint name suggests it relates to IP-MAC binding configuration, a critical network security feature. Exploitation could allow attackers to bypass network access controls, inject malicious configurations, or disrupt device operation. Although no confirmed exploits are currently active in the wild, the public disclosure of exploit details increases the likelihood of future attacks. The vulnerability affects a widely deployed consumer and small business router model, which may be present in various organizational networks. The lack of an official patch link indicates that vendors or users may need to rely on interim mitigations until a firmware update is released.

For European organizations, this vulnerability poses a significant risk as it can lead to full compromise of Tenda TX3 routers, which serve as critical network gateways. Successful exploitation could allow attackers to intercept, modify, or redirect network traffic, undermining confidentiality and integrity of communications. It could also enable denial of service by crashing the device or corrupting its configuration, impacting availability. Organizations relying on these routers for perimeter security or internal segmentation may face increased exposure to lateral movement and data exfiltration. The remote, unauthenticated nature of the exploit lowers the barrier for attackers, including cybercriminals and state-sponsored actors. Given the strategic importance of telecommunications infrastructure in Europe, attacks exploiting this vulnerability could disrupt business operations, critical services, or government networks. The absence of a patch increases the urgency for organizations to implement compensating controls. Additionally, the public disclosure of exploit details may lead to rapid weaponization, increasing the threat landscape for European entities.

1. Immediately restrict remote access to the /goform/SetIpMacBind endpoint by implementing firewall rules or access control lists that limit management interface exposure to trusted IP addresses only. 2. Disable remote management features on Tenda TX3 routers if not strictly necessary, especially WAN-side access. 3. Monitor network traffic for unusual or malformed requests targeting /goform/SetIpMacBind and set up alerts for potential exploitation attempts. 4. Employ network intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics to detect buffer overflow attempts against Tenda devices. 5. Segment networks to isolate vulnerable routers from critical assets and reduce attack surface. 6. Engage with Tenda support or vendor channels to obtain firmware updates or patches as soon as they become available. 7. Consider replacing Tenda TX3 devices with alternative hardware if patching is delayed and risk is unacceptable. 8. Conduct regular vulnerability assessments and penetration testing focusing on network infrastructure devices to identify and remediate similar issues proactively.