CVE-2026-1742: EFM ipTIME A8004T RCE Vulnerability

CVE-2026-1742 Overview

A vulnerability has been identified in EFM ipTIME A8004T firmware version 14.18.2 affecting the VPN Service component. The vulnerability exists in the commit_vpncli_file_upload function within the /cgi/timepro.cgi file, allowing unrestricted file uploads. This improper access control flaw enables remote attackers with high privileges to upload arbitrary files to the affected device, potentially leading to system compromise.

Critical Impact

Remote attackers can exploit unrestricted file upload functionality in the VPN Service component to upload malicious files to vulnerable ipTIME A8004T routers, potentially leading to device compromise and network infiltration.

Affected Products

• EFM ipTIME A8004T firmware version 14.18.2
• ipTIME A8004T VPN Service component
• /cgi/timepro.cgi file handling component

Discovery Timeline

• 2026-02-02 - CVE-2026-1742 published to NVD
• 2026-02-03 - Last updated in NVD database

Technical Details for CVE-2026-1742

Vulnerability Analysis

This vulnerability is classified under CWE-284 (Improper Access Control), indicating that the affected system fails to properly restrict access to the file upload functionality. The commit_vpncli_file_upload function in the VPN Service component does not implement adequate validation or authorization checks when processing file uploads through the /cgi/timepro.cgi endpoint.

The vulnerability allows an authenticated attacker with administrative privileges to upload files without proper restrictions on file type, content, or destination. While the attack requires high privileges (authenticated administrative access), it can be executed remotely over the network without user interaction. The exploit has been publicly disclosed, and the vendor (EFM) was contacted about this vulnerability but did not respond.

Root Cause

The root cause of this vulnerability lies in the improper access control implementation within the commit_vpncli_file_upload function. The VPN Service component fails to implement proper file upload restrictions, including:

• Insufficient validation of uploaded file types and extensions
• Lack of content verification for uploaded files
• Missing restrictions on upload destinations
• Inadequate authorization checks for the file upload operation

This allows authenticated users to bypass intended security restrictions and upload arbitrary files to the device.

Attack Vector

The attack vector for CVE-2026-1742 is network-based, allowing remote exploitation. An attacker with administrative credentials can target the vulnerable /cgi/timepro.cgi endpoint and invoke the commit_vpncli_file_upload function to upload malicious files.

The attack flow typically involves:

1. Authenticating to the ipTIME A8004T administrative interface with valid credentials
2. Crafting a malicious HTTP request targeting the VPN file upload functionality
3. Uploading arbitrary files through the unrestricted upload mechanism
4. Potentially achieving code execution or persistent access depending on the uploaded content

For technical details and proof-of-concept information, refer to the GitHub CVE Issue Discussion.

Detection Methods for CVE-2026-1742

Indicators of Compromise

• Unusual HTTP POST requests to /cgi/timepro.cgi with file upload parameters
• Unexpected files appearing in VPN configuration directories on ipTIME devices
• Anomalous administrative login activity followed by file upload operations

Detection Strategies

• Monitor network traffic for HTTP requests targeting /cgi/timepro.cgi with the commit_vpncli_file_upload function
• Implement intrusion detection rules to flag suspicious file upload activity to ipTIME router management interfaces
• Review web server logs on affected devices for unusual CGI requests containing file upload parameters

Monitoring Recommendations

• Enable logging on ipTIME A8004T devices to capture administrative actions and file operations
• Deploy network monitoring solutions to detect unauthorized access attempts to router management interfaces
• Implement alerting for any file upload activity to the VPN Service component
• Regularly audit device configurations and filesystem integrity to detect unauthorized modifications

How to Mitigate CVE-2026-1742

Immediate Actions Required

• Restrict network access to the ipTIME A8004T administrative interface to trusted IP addresses only
• Implement strong authentication credentials and change default passwords immediately
• Place affected devices behind a firewall and disable remote management if not required
• Monitor device logs for signs of exploitation attempts

Patch Information

As of the last update on 2026-02-03, the vendor (EFM) has not released a security patch for this vulnerability. The vendor was contacted about this disclosure but did not respond. Users should monitor the VulDB entry for updates on patch availability and consult official ipTIME support channels for firmware updates.

Workarounds

• Disable the VPN Service component if not actively required
• Implement network segmentation to isolate vulnerable devices from critical network segments
• Use firewall rules to block external access to the device management interface
• Consider deploying an alternative router solution until a patch is available

# Network access restriction example (firewall rule)
# Restrict access to router management interface to internal network only
iptables -A INPUT -p tcp --dport 80 -s 192.168.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -s 192.168.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP