CVE-2026-41037: Quantum Networks Router Auth Bypass Flaw

CVE-2026-41037 Overview

This vulnerability exists in Quantum Networks router due to missing rate limiting and CAPTCHA protection for failed login attempts in the web-based management interface. An attacker on the same network could exploit this vulnerability by performing brute force attacks against administrative credentials, leading to unauthorized access with root privileges on the targeted device.

Critical Impact

Successful exploitation allows an adjacent network attacker to gain full administrative control over the router with root privileges through credential brute forcing.

Affected Products

• Quantum Networks Router (web-based management interface)

Discovery Timeline

• 2026-04-21 - CVE CVE-2026-41037 published to NVD
• 2026-04-21 - Last updated in NVD database

Technical Details for CVE-2026-41037

Vulnerability Analysis

This vulnerability is classified as CWE-307 (Improper Restriction of Excessive Authentication Attempts). The web-based management interface of the Quantum Networks router lacks fundamental security controls to prevent credential guessing attacks. Without rate limiting mechanisms or CAPTCHA challenges, the authentication system will accept an unlimited number of login attempts without imposing delays, lockouts, or additional verification requirements.

The adjacent network attack vector means that an attacker must be on the same local network segment as the vulnerable router to exploit this vulnerability. Once positioned on the network, the attacker can automate credential guessing attempts against the administrative login page at high speeds, significantly increasing the probability of discovering valid credentials.

Root Cause

The root cause of this vulnerability is the absence of proper authentication rate limiting and anti-automation controls in the router's web management interface. The authentication mechanism does not implement:

• Account lockout policies after failed login attempts
• Progressive delays between authentication requests
• CAPTCHA or similar human verification challenges
• IP-based request throttling

This design flaw allows attackers to submit thousands of authentication requests without any defensive measures being triggered.

Attack Vector

The attack requires adjacent network access, meaning the attacker must be on the same network segment as the target router. From this position, the attacker can target the web-based management interface login page with automated credential guessing tools. Common attack methodologies include dictionary attacks using lists of common passwords, credential stuffing using previously compromised credentials, and exhaustive brute force attacks against short or weak passwords.

Upon successful credential discovery, the attacker gains root-level administrative access to the device, enabling complete control over router configuration, network traffic manipulation, and potential use as a pivot point for further network intrusion.

Detection Methods for CVE-2026-41037

Indicators of Compromise

• Unusual volume of HTTP/HTTPS requests to the router's management interface login endpoint
• Multiple failed authentication attempts from the same source IP address within short time periods
• Successful login events following a pattern of numerous failed attempts
• Authentication logs showing rapid sequential login attempts with different credential combinations

Detection Strategies

• Monitor web server access logs on the router for patterns indicative of automated login attempts
• Deploy network monitoring to detect high-frequency connection attempts to the management interface port
• Configure SIEM rules to alert on authentication anomalies against network infrastructure devices
• Implement network segmentation monitoring to detect unauthorized devices on management VLANs

Monitoring Recommendations

• Enable verbose authentication logging on the router if supported
• Deploy network intrusion detection systems (NIDS) with rules for HTTP brute force detection
• Monitor for unusual administrative configuration changes following authentication events
• Review router access logs regularly for signs of credential compromise

How to Mitigate CVE-2026-41037

Immediate Actions Required

• Restrict access to the web management interface to specific trusted IP addresses or management VLANs
• Implement network-level rate limiting using upstream firewall or network devices
• Change default administrative credentials to strong, complex passwords
• Consider disabling the web-based management interface and using alternative management methods such as SSH or console access

Patch Information

Refer to the CERT-IN Advisory CIVN-2026-0200 for official vendor patch information and updates. Organizations should contact Quantum Networks directly for firmware updates that address this vulnerability.

Workarounds

• Implement access control lists (ACLs) to restrict management interface access to authorized administrator workstations only
• Deploy a Web Application Firewall (WAF) or reverse proxy in front of the management interface with rate limiting capabilities
• Enable multi-factor authentication if supported by the device firmware
• Segment the management network from user networks to limit attacker access to the vulnerable interface
• Consider temporarily disabling the web management interface until a patch is available

# Example ACL configuration to restrict management access
# (Syntax may vary by device - consult Quantum Networks documentation)
ip access-list extended MGMT-RESTRICT
 permit tcp host 192.168.1.100 any eq 443
 permit tcp host 192.168.1.101 any eq 443
 deny tcp any any eq 443 log