CVE-2026-101077: Netcore NR289-GE Auth Bypass Vulnerability

CVE-2026-101077 Overview

CVE-2026-101077 is a missing authentication vulnerability [CWE-287] in the Netcore NR289-GE router running firmware version 1.4.5102. The flaw resides in the process_request function of the boa_temp Handler component. An unauthenticated remote attacker can reach the vulnerable handler over the network and perform file write operations without credentials. A public exploit has been released, and the vendor did not respond to disclosure attempts.

Critical Impact

Unauthenticated remote attackers can write arbitrary files to the device, enabling configuration tampering, persistence, and potential full device compromise.

Affected Products

• Netcore NR289-GE Router
• Firmware version 1.4.5102 (build 2018.06.1418_44)
• boa_temp Handler component (process_request function)

Discovery Timeline

• 2026-09-28 - CVE-2026-101077 published to NVD
• 2026-09-28 - Last updated in NVD database

Technical Details for CVE-2026-101077

Vulnerability Analysis

The vulnerability affects the embedded boa web server component shipped with the Netcore NR289-GE router. The process_request routine inside the boa_temp Handler does not enforce authentication before processing incoming HTTP requests. An attacker reachable on the router's management interface can therefore invoke privileged file write functionality without presenting any credentials.

The weakness is classified as Missing Authentication for Critical Function [CWE-287]. Because the router typically exposes its web interface on the local network, and in some deployments on WAN-facing addresses, the attack surface is wide. The vendor was contacted but did not respond, and no official patch is available.

Root Cause

The root cause is the absence of an authentication check inside the process_request function of the boa_temp Handler. The handler accepts requests and performs file write operations without verifying session tokens, cookies, or Basic Authentication credentials. This design flaw permits anonymous access to functionality that should be restricted to authenticated administrative users.

Attack Vector

Exploitation requires network access to the router's HTTP management interface. The attacker sends a crafted HTTP request to the vulnerable boa_temp endpoint, which the server processes without checking authentication state. The attacker can then write arbitrary content to files on the device, which may be used to overwrite configuration data, drop a web shell, or stage further compromise of the device firmware.

The vulnerability mechanism is documented in the public write-up on the GitHub Unauthenticated File Write disclosure and tracked in the VulDB CVE-2026-101077 record. No verified exploit code is reproduced here.

Detection Methods for CVE-2026-101077

Indicators of Compromise

• Unauthenticated HTTP requests to the boa_temp endpoint of the router's management interface
• Unexpected file modifications on the router filesystem, including configuration files or web content
• New or modified files served from the embedded boa web server document root
• Outbound connections from the router to unknown hosts following suspicious inbound HTTP traffic

Detection Strategies

• Inspect router access logs for HTTP requests reaching boa_temp handler paths without a prior authenticated session
• Deploy network intrusion detection signatures that flag unauthenticated POST requests to the router's management ports
• Monitor for unusual HTTP traffic patterns originating from untrusted segments and destined to router management addresses
• Baseline device file hashes and alert on unexpected changes to firmware-resident files

Monitoring Recommendations

• Centralize router syslog output to a SIEM for correlation with network flow data
• Alert on management-plane HTTP traffic sourced from the WAN interface or non-administrative VLANs
• Track and investigate device reboots or configuration reloads that follow inbound HTTP activity

How to Mitigate CVE-2026-101077

Immediate Actions Required

• Restrict access to the router's web management interface to trusted management VLANs only
• Disable WAN-side administration if currently enabled on affected NR289-GE devices
• Place vulnerable devices behind a network firewall that blocks inbound HTTP to the router
• Consider replacing the device, since the vendor did not respond to the disclosure and no patch is available

Patch Information

According to the disclosure, the vendor was contacted early but did not respond. No official security patch has been published for Netcore NR289-GE firmware 1.4.5102 at the time of CVE publication. Monitor the VulDB vulnerability record 410948 for any future vendor action.

Workarounds

• Enforce network segmentation to isolate the router's management interface from user and guest networks
• Apply access control lists that permit management traffic only from designated administrator hosts
• Place the router behind an upstream firewall or NAT device that terminates untrusted inbound HTTP
• Where feasible, replace the device with hardware receiving active security maintenance

# Example upstream firewall rule to block inbound HTTP to router management
# Replace ROUTER_IP and MGMT_SUBNET with your values
iptables -I FORWARD -p tcp -d ROUTER_IP --dport 80 -j DROP
iptables -I FORWARD -p tcp -s MGMT_SUBNET -d ROUTER_IP --dport 80 -j ACCEPT