CVE-2025-68717: KAYSUS Router Auth Bypass Vulnerability

CVE-2025-68717 Overview

CVE-2025-68717 is a critical authentication bypass vulnerability affecting KAYSUS KS-WR3600 routers running firmware version 1.0.5.9.1. The vulnerability exists in the session validation mechanism, allowing unauthenticated attackers to piggyback on active user sessions to access privileged endpoints. When any legitimate user is logged into the router, endpoints such as /cgi-bin/system-tool improperly accept requests with empty or invalid session values, enabling attackers to retrieve sensitive configuration data or execute privileged administrative actions without proper authentication.

Critical Impact

Attackers can bypass authentication entirely to access sensitive router configurations and execute privileged commands when any user has an active session, potentially leading to complete device compromise.

Affected Products

• KAYSUS KS-WR3600 WiFi 7 BE3600 Wireless Router
• Firmware version 1.0.5.9.1
• Devices with active user sessions (required for exploitation)

Discovery Timeline

• January 8, 2026 - CVE-2025-68717 published to NVD
• January 8, 2026 - Last updated in NVD database

Technical Details for CVE-2025-68717

Vulnerability Analysis

This authentication bypass vulnerability (CWE-287) stems from a fundamental design flaw in how the KAYSUS KS-WR3600 router validates user sessions. The router's web management interface fails to properly enforce authentication checks when processing requests to privileged CGI endpoints.

Under normal circumstances, authenticated sessions should be cryptographically validated for each request, ensuring that only the legitimate session holder can access protected resources. However, the vulnerable firmware implementation accepts requests with empty or malformed session tokens as long as at least one user is currently logged into the device. This creates a race condition where any network-adjacent attacker can "piggyback" on an existing authenticated session.

The attack surface is network-accessible, requiring no user interaction and no prior privileges. The vulnerability enables unauthorized access to sensitive device configurations and the ability to execute privileged administrative functions, posing significant risks to confidentiality and integrity of the affected network infrastructure.

Root Cause

The root cause is improper authentication validation in the router's CGI request handling. The session validation logic appears to check whether any session exists rather than verifying that the incoming request contains a valid session token that matches an authenticated user. This flawed logic allows attackers to submit requests with empty or invalid session values that are incorrectly accepted by the system.

Attack Vector

The attack can be executed remotely over the network by any attacker who can reach the router's web management interface. The exploitation scenario requires:

1. A legitimate user to be currently logged into the router's web interface
2. The attacker to send HTTP requests to vulnerable CGI endpoints (e.g., /cgi-bin/system-tool) with empty or invalid session cookies
3. The router improperly accepts these requests and processes them as if they were authenticated

The attack does not require any credentials, prior privileges, or user interaction. Once exploited, attackers can extract sensitive configuration data including WiFi credentials, network configurations, and potentially execute administrative commands that could reconfigure or compromise the device.

Due to the nature of this vulnerability, no synthetic code examples are provided. Technical details and proof-of-concept information can be found in the GitHub PoC Repository.

Detection Methods for CVE-2025-68717

Indicators of Compromise

• Unexpected HTTP requests to /cgi-bin/system-tool or similar CGI endpoints from unknown IP addresses
• Web server logs showing requests with missing, empty, or malformed session cookies that receive successful responses
• Configuration changes or data exports that were not initiated by authorized administrators
• Multiple requests to administrative endpoints from different source IPs within short time windows

Detection Strategies

• Monitor web server access logs for requests to CGI endpoints containing empty or invalid session parameters
• Implement network intrusion detection rules to alert on unauthenticated access attempts to router management interfaces
• Deploy honeypot configurations to detect reconnaissance activity targeting KAYSUS router endpoints
• Review access logs for successful responses to requests lacking proper authentication headers

Monitoring Recommendations

• Enable comprehensive logging on all KAYSUS KS-WR3600 router management interfaces
• Implement real-time alerting for any access to administrative CGI endpoints from external or untrusted network segments
• Regularly audit configuration files and compare against known-good baselines to detect unauthorized modifications
• Monitor for anomalous network traffic patterns targeting the router's management port

How to Mitigate CVE-2025-68717

Immediate Actions Required

• Restrict access to the router's web management interface to trusted IP addresses only using firewall rules
• Disable remote administration if not absolutely required for operations
• Implement network segmentation to isolate the router management interface from untrusted network segments
• Monitor for firmware updates from KAYSUS and apply patches immediately when available

Patch Information

As of the publication date, no official patch has been released by KAYSUS for this vulnerability. Organizations should monitor the Kaysus Product Page for security updates and firmware releases. Additional technical information is available in the GitHub CVE Collection.

Workarounds

• Configure access control lists (ACLs) to restrict web management interface access to specific administrator IP addresses only
• Place the router behind a separate firewall that enforces authentication before allowing access to the management interface
• Consider disabling the web management interface entirely and using only local console access for administration
• Implement a VPN requirement for all remote administrative access to the network infrastructure

# Example firewall rule to restrict management interface access (iptables)
# Restrict access to router management port (typically 80/443) to trusted admin IP only
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.100 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.100 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP