CVE-2026-1740: ipTIME A8004T Auth Bypass Vulnerability

CVE-2026-1740 Overview

A vulnerability has been identified in EFM ipTIME A8004T version 14.18.2 that allows attackers to bypass authentication mechanisms. This improper authentication flaw impacts the httpcon_check_session_url function within the /cgi/timepro.cgi file, specifically within the Hidden Hiddenloginsetup Interface component. The vulnerability can be exploited remotely without requiring prior authentication, potentially allowing unauthorized access to the device's management interface and configuration settings.

Critical Impact

Remote attackers can bypass authentication on affected ipTIME routers, potentially gaining unauthorized access to network configuration and administrative functions without valid credentials.

Affected Products

• EFM ipTIME A8004T firmware version 14.18.2
• Devices with the Hidden Hiddenloginsetup Interface enabled
• Network environments using vulnerable ipTIME router configurations

Discovery Timeline

• 2026-02-02 - CVE CVE-2026-1740 published to NVD
• 2026-02-03 - Last updated in NVD database

Technical Details for CVE-2026-1740

Vulnerability Analysis

This authentication bypass vulnerability (CWE-287) affects the session validation mechanism in the ipTIME A8004T router's web management interface. The flaw exists in how the httpcon_check_session_url function processes authentication requests through the /cgi/timepro.cgi endpoint.

The vulnerability allows remote attackers to circumvent the normal authentication flow by exploiting weaknesses in the Hidden Hiddenloginsetup Interface. When successfully exploited, attackers can gain access to restricted functionality without providing valid credentials. The exploit has been publicly disclosed, increasing the risk of active exploitation in the wild.

The vendor (EFM) was contacted during the responsible disclosure process but did not respond, leaving users without an official remediation path at this time.

Root Cause

The root cause of this vulnerability is improper authentication validation in the httpcon_check_session_url function. The Hidden Hiddenloginsetup Interface does not properly verify session tokens or user credentials before granting access to protected resources. This implementation flaw allows requests to bypass the standard authentication checks, providing unauthorized access to the device's administrative functions.

Attack Vector

The attack vector is network-based, meaning an attacker can exploit this vulnerability remotely without physical access to the device. The exploitation requires no user interaction and no prior privileges on the target system. An attacker on the same network or with access to the router's management interface can:

1. Send crafted HTTP requests to the /cgi/timepro.cgi endpoint
2. Manipulate the session validation flow through the Hidden Hiddenloginsetup Interface
3. Bypass authentication checks in the httpcon_check_session_url function
4. Gain unauthorized access to administrative functions

Technical details and proof-of-concept information have been documented in the GitHub CVE Issue Discussion and VulDB #343639.

Detection Methods for CVE-2026-1740

Indicators of Compromise

• Unexpected administrative sessions on the ipTIME router without corresponding login events
• Unusual HTTP requests to /cgi/timepro.cgi from unauthorized IP addresses
• Configuration changes made without authenticated administrator actions
• Access logs showing requests to the Hidden Hiddenloginsetup Interface from external sources

Detection Strategies

• Monitor HTTP access logs for requests targeting /cgi/timepro.cgi with anomalous parameters
• Implement network-based intrusion detection rules to identify authentication bypass attempts
• Review router access logs for sessions initiated without successful authentication events
• Deploy SentinelOne Singularity for network traffic analysis and behavioral detection of exploitation attempts

Monitoring Recommendations

• Enable verbose logging on the ipTIME router if supported to capture detailed request information
• Implement SIEM alerting for multiple failed authentication attempts followed by successful access
• Monitor network traffic for unusual patterns targeting the router's management interface
• Regularly audit active sessions and administrative access on the device

How to Mitigate CVE-2026-1740

Immediate Actions Required

• Restrict access to the router's web management interface to trusted internal networks only
• Disable remote management features if not required for operations
• Implement firewall rules to block external access to the /cgi/timepro.cgi endpoint
• Consider network segmentation to isolate management interfaces from untrusted networks

Patch Information

At the time of publication, no official patch is available from EFM. The vendor was contacted during disclosure but did not respond. Users should monitor the vendor's website and security bulletins for future firmware updates. Additional details can be found in the VulDB CTI ID #343639 and VulDB Submission #741422.

Workarounds

• Restrict administrative access to the router to specific trusted IP addresses using firewall ACLs
• Disable the web management interface and use alternative management methods if available
• Place the router's management interface on an isolated VLAN accessible only to authorized administrators
• Monitor the device for unauthorized access attempts until an official patch becomes available

# Example firewall rule to restrict access to management interface (adapt to your firewall)
# Block external access to the CGI endpoint
iptables -A INPUT -p tcp --dport 80 -d <router_ip> -s ! <trusted_network> -j DROP
iptables -A INPUT -p tcp --dport 443 -d <router_ip> -s ! <trusted_network> -j DROP