CVE-2026-31850: Nexxt Nebula 300+ Information Disclosure

CVE-2026-31850 Overview

CVE-2026-31850 is a sensitive information exposure vulnerability affecting Nexxt Solutions Nebula 300+ wireless routers running firmware through version 12.01.01.37. The vulnerability stems from improper storage of credentials, where administrative credentials and WiFi pre-shared keys are stored in plaintext within exported configuration backup files.

This firmware vulnerability allows attackers who can obtain configuration backup files—either through legitimate administrative access, social engineering, or by exploiting other weaknesses in the device—to directly extract sensitive credentials without any cryptographic protections such as encryption or hashing.

Critical Impact

Administrative credentials and WiFi pre-shared keys can be extracted in plaintext from configuration backup files, enabling full device takeover and unauthorized network access.

Affected Products

• Nexxt Solutions Nebula 300+ firmware through version 12.01.01.37
• Nexxt Solutions ARN02304U6 product line

Discovery Timeline

• 2026-03-23 - CVE CVE-2026-31850 published to NVD
• 2026-03-26 - Last updated in NVD database

Technical Details for CVE-2026-31850

Vulnerability Analysis

This vulnerability is classified under CWE-256 (Plaintext Storage of a Password), a category of weaknesses where sensitive authentication credentials are stored without adequate cryptographic protection. The Nexxt Solutions Nebula 300+ router provides functionality to export device configuration as backup files for restoration or migration purposes. However, these exported configuration files contain sensitive data—including administrative login credentials and WiFi pre-shared keys (PSKs)—in completely unprotected plaintext format.

When an attacker gains access to such a backup file, they can immediately read all stored credentials without needing to perform any decryption, hash cracking, or other cryptanalytic attacks. This represents a fundamental failure in protecting sensitive authentication material at rest.

Root Cause

The root cause of this vulnerability is the absence of any encryption or hashing mechanism applied to sensitive credential data within the firmware's configuration export functionality. The developers failed to implement cryptographic protections for stored passwords and pre-shared keys, violating fundamental secure development practices for credential storage. Configuration backup mechanisms should either encrypt sensitive fields using device-specific or user-supplied keys, or completely omit credentials from exported configurations.

Attack Vector

The attack vector requires adjacent network access and high privileges on the device itself. An attacker must first obtain a configuration backup file through one of several methods:

1. Direct administrative access: An attacker with compromised or default administrative credentials can legitimately export the configuration through the router's web interface.

2. Local network access: An attacker on the same network segment may exploit other vulnerabilities or weaknesses to download configuration files.

3. Physical access: An attacker with physical access to the device or a user's computer may recover previously exported backup files.

4. Social engineering: An attacker may trick a legitimate administrator into sharing backup files under false pretenses (e.g., posing as technical support).

Once the backup file is obtained, the attacker simply opens it with a text editor or parses it programmatically to extract all stored credentials in clear text. With the administrative password, the attacker gains full control of the router. With the WiFi PSK, the attacker can join the wireless network and potentially pivot to attack other connected devices.

Detection Methods for CVE-2026-31850

Indicators of Compromise

• Unexpected configuration backup exports appearing in device logs
• Unauthorized access to the router's administrative interface from unknown IP addresses
• Configuration changes made by unrecognized sessions
• New or modified user accounts in the router's administrative panel
• WiFi client connections from unrecognized MAC addresses following potential credential exposure

Detection Strategies

• Monitor router administrative logs for configuration export operations, especially from unusual times or IP addresses
• Implement network monitoring to detect unauthorized administrative access attempts to the router's management interface
• Track file access patterns on systems where configuration backups are stored
• Deploy network intrusion detection to identify reconnaissance activity targeting network infrastructure devices

Monitoring Recommendations

• Enable comprehensive logging on the Nexxt Solutions Nebula 300+ device if supported
• Review administrative access logs regularly for anomalous export or download activity
• Monitor for new wireless client connections that may indicate compromised WiFi credentials
• Implement alerts for configuration changes or administrative access from unexpected sources

How to Mitigate CVE-2026-31850

Immediate Actions Required

• Avoid exporting configuration backups until a firmware update addressing this issue is available
• If backups must be created, encrypt the resulting files using external encryption tools before storage
• Store any existing configuration backup files in encrypted containers with restricted access
• Rotate administrative credentials and WiFi pre-shared keys if configuration backups may have been exposed
• Restrict administrative access to the router to trusted devices and networks only

Patch Information

No vendor patch information is currently available for this vulnerability. Users should monitor the Nexxt Solutions product page for firmware updates that address this security issue. The affected firmware version 12.01.01.37 and earlier should be updated once a patched version becomes available.

Additional technical documentation can be found at the Nexxt Connectivity Documentation resource.

Workarounds

• Encrypt all configuration backup files manually using strong encryption (e.g., AES-256) before storing or transmitting them
• Limit administrative access to the router to a dedicated management VLAN or wired connection only
• Implement network segmentation to isolate the router's management interface from general network traffic
• Use unique, complex passwords for administrative access that are changed regularly
• Consider replacing the device with hardware from vendors that implement proper credential protection in backup files

# Example: Encrypt backup files manually before storage
# After exporting configuration, encrypt with OpenSSL
openssl enc -aes-256-cbc -salt -pbkdf2 -in router_backup.cfg -out router_backup.cfg.enc

# Securely delete the plaintext backup
shred -u router_backup.cfg