CVE-2026-41038: Quantum Networks Router Auth Bypass Flaw

CVE-2026-41038 Overview

This vulnerability exists in Quantum Networks router due to lack of enforcement of strong password policies in the web-based management interface. An attacker on the same network could exploit this vulnerability by performing password guessing or brute-force attacks against user accounts, leading to unauthorized access to the targeted device.

Critical Impact

Adjacent network attackers can exploit weak password policy enforcement to gain unauthorized access to the router management interface through brute-force or password guessing attacks, potentially compromising network infrastructure.

Affected Products

• Quantum Networks Router (web-based management interface)

Discovery Timeline

• 2026-04-21 - CVE-2026-41038 published to NVD
• 2026-04-21 - Last updated in NVD database

Technical Details for CVE-2026-41038

Vulnerability Analysis

This vulnerability stems from CWE-521 (Weak Password Requirements), a configuration and design flaw that allows attackers to exploit insufficient password policy enforcement. The web-based management interface of Quantum Networks routers fails to implement adequate password strength requirements, leaving user accounts susceptible to credential-based attacks.

The attack requires adjacent network access, meaning the attacker must be on the same local network segment as the target device. While the attack complexity is considered high, no user interaction or prior privileges are required for exploitation. Successful exploitation results in high confidentiality and integrity impact to the vulnerable device, with limited impact to availability.

Root Cause

The root cause of this vulnerability is the lack of enforcement of strong password policies in the router's web-based management interface. The system fails to require adequate password complexity, length, or character diversity, enabling attackers to successfully guess or brute-force user credentials. This represents a fundamental authentication security weakness where password strength requirements are either absent or insufficiently enforced.

Attack Vector

The attack vector is classified as Adjacent Network, requiring the attacker to have access to the same network segment as the vulnerable Quantum Networks router. From this position, an attacker can target the web-based management interface by performing systematic password guessing or brute-force attacks against user accounts.

The exploitation process typically involves:

1. Network reconnaissance to identify the router's management interface
2. Enumeration of valid usernames if not properly protected
3. Systematic password guessing using common passwords or dictionary lists
4. Brute-force attacks to try password combinations until successful authentication
5. Unauthorized access to the router's administrative functions upon credential discovery

The lack of account lockout mechanisms or rate limiting may further facilitate these attacks, allowing attackers to attempt numerous authentication requests without being blocked.

Detection Methods for CVE-2026-41038

Indicators of Compromise

• Multiple failed authentication attempts against the router management interface from single or multiple source IPs within the local network
• Unusual authentication patterns showing rapid sequential login attempts
• Successful logins following a series of failed authentication attempts
• Administrative access from unexpected internal network addresses

Detection Strategies

• Implement logging and monitoring for authentication events on network infrastructure devices
• Configure SIEM rules to detect brute-force patterns such as multiple failed logins followed by success
• Monitor for anomalous administrative sessions on network devices outside of expected maintenance windows
• Review authentication logs for password spraying patterns across multiple user accounts

Monitoring Recommendations

• Enable comprehensive authentication logging on Quantum Networks routers if supported
• Establish baseline authentication patterns for administrative access to network infrastructure
• Configure alerts for threshold-based authentication failures from adjacent network segments
• Regularly audit user accounts and access logs for the router management interface

How to Mitigate CVE-2026-41038

Immediate Actions Required

• Implement strong, unique passwords for all user accounts on affected Quantum Networks routers immediately
• Restrict management interface access to trusted administrator workstations via network segmentation or ACLs
• Enable account lockout policies if configurable on the device
• Disable unnecessary user accounts on the router management interface
• Monitor authentication logs for signs of ongoing brute-force attempts

Patch Information

Organizations should consult the CERT-IN Vulnerability Note CIVN-2026-0200 for official guidance and any available patches or firmware updates from Quantum Networks. Apply vendor-provided security updates as soon as they become available.

Workarounds

• Enforce administrative password policies manually by requiring complex passwords with minimum length, mixed case, numbers, and special characters
• Implement network segmentation to isolate router management interfaces from general network access
• Configure access control lists (ACLs) to limit management interface access to specific trusted IP addresses
• Consider placing the management interface on a dedicated out-of-band management network
• Enable two-factor authentication if supported by the device

# Example ACL configuration to restrict management access (syntax varies by device)
# Restrict web management interface access to trusted admin subnet only
access-list mgmt-acl permit ip 192.168.100.0/24 any
access-list mgmt-acl deny ip any any
interface web-management
  ip access-group mgmt-acl in