CVE-2026-1740 is an authentication bypass vulnerability identified in the EFM ipTIME A8004T router firmware version 14.18.2. The flaw exists in the function httpcon_check_session_url within the /cgi/timepro.cgi script, which is part of a hidden login setup interface. Due to improper validation of session URLs, an attacker can remotely bypass authentication controls without requiring any privileges or user interaction. This allows unauthorized remote access to the router's administrative interface or other sensitive functions. The vulnerability does not require authentication, making it exploitable over the network with low attack complexity. The CVSS 4.0 base score is 6.9 (medium severity), reflecting the potential for partial impact on confidentiality, integrity, and availability. The vendor EFM was contacted early but has not provided any patches or mitigation guidance, and no official fixes are currently available. Although no active exploitation in the wild has been reported, public disclosure of exploit details increases the risk of future attacks. This vulnerability could be leveraged by attackers to gain control over the router, manipulate network traffic, or pivot into internal networks, especially in environments where these devices are used as gateways or for remote access.

For European organizations, exploitation of this vulnerability could lead to unauthorized administrative access to affected routers, enabling attackers to intercept or manipulate network traffic, disrupt network availability, or establish persistent footholds within corporate networks. This is particularly critical for organizations relying on EFM ipTIME A8004T devices for perimeter defense or remote connectivity. Confidentiality of sensitive data traversing the network could be compromised, and integrity of network configurations could be altered, leading to potential data breaches or service disruptions. The lack of vendor response and patches increases the risk exposure period. Critical infrastructure sectors, SMEs, and enterprises using these routers without additional security controls are at heightened risk. The vulnerability's remote exploitability without authentication or user interaction makes it a significant threat vector for automated scanning and exploitation campaigns targeting vulnerable devices in Europe.

Given the absence of official patches, European organizations should implement immediate compensating controls. These include disabling remote management interfaces on the ipTIME A8004T devices to prevent external access to the vulnerable CGI endpoint. Network segmentation should be enforced to isolate these routers from critical internal networks. Deploy strict firewall rules to restrict access to router management ports only to trusted administrative hosts within the local network. Continuous monitoring and logging of router access attempts should be enabled to detect anomalous activities. Where possible, replace affected devices with alternative models from vendors with active security support. Additionally, organizations should conduct regular vulnerability scans to identify exposed ipTIME A8004T devices and prioritize remediation. Educating network administrators about this vulnerability and the importance of minimizing attack surfaces on network devices is also crucial.