CVE-2026-2056: D-Link DIR-605L Information Disclosure

CVE-2026-2056 Overview

A security vulnerability has been detected in D-Link DIR-605L and DIR-619L routers running firmware versions 2.06B01 and 2.13B01. The impacted element is an unknown function of the file /wan_connection_status.asp within the DHCP Connection Status Handler component. The manipulation of this component leads to information disclosure. Remote exploitation of the attack is possible, and the exploit has been disclosed publicly. This vulnerability only affects products that are no longer supported by the maintainer.

Critical Impact

End-of-life D-Link routers are vulnerable to remote information disclosure through the DHCP Connection Status Handler, potentially exposing sensitive network configuration data to unauthenticated attackers.

Affected Products

• D-Link DIR-605L (Firmware 2.06B01)
• D-Link DIR-619L (Firmware 2.06B01)
• D-Link DIR-619L (Firmware 2.13B01)

Discovery Timeline

• 2026-02-06 - CVE-2026-2056 published to NVD
• 2026-02-06 - Last updated in NVD database

Technical Details for CVE-2026-2056

Vulnerability Analysis

This vulnerability is classified as CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor). The flaw exists in the DHCP Connection Status Handler component, specifically within the /wan_connection_status.asp file. Due to improper access controls and input validation, an attacker can remotely access this endpoint to extract sensitive information about the router's network configuration and WAN connection status.

The vulnerability is particularly concerning because it affects end-of-life devices that will not receive security patches from D-Link. The network-accessible nature of this flaw means attackers can exploit it without requiring authentication or local access to the device.

Root Cause

The root cause of this vulnerability stems from insufficient access controls on the /wan_connection_status.asp endpoint. The DHCP Connection Status Handler fails to properly validate whether incoming requests are authorized to access sensitive WAN connection information. This allows unauthenticated remote attackers to query the endpoint and retrieve internal network configuration details that should only be accessible to authenticated administrators.

Attack Vector

The attack vector is network-based, allowing remote exploitation without user interaction. An attacker with network access to the vulnerable router can directly query the /wan_connection_status.asp endpoint to retrieve sensitive information. The attack requires no special privileges or authentication, making it trivial to exploit on exposed devices.

The exploitation mechanism involves sending specially crafted HTTP requests to the vulnerable ASP file. Since the DHCP Connection Status Handler does not implement proper authorization checks, it returns sensitive WAN connection status data to any requester.

Technical details and proof-of-concept information are available in the GitHub PoC Repository and GitHub Vulnerability Documentation.

Detection Methods for CVE-2026-2056

Indicators of Compromise

• Unusual HTTP requests to /wan_connection_status.asp from external IP addresses
• Unexpected access patterns to the router's web management interface
• Network reconnaissance activity targeting D-Link router management ports (typically port 80 or 443)
• Log entries showing repeated queries to DHCP status endpoints without authentication

Detection Strategies

• Monitor web server access logs for requests to /wan_connection_status.asp from untrusted sources
• Implement network-level detection rules for HTTP requests containing the vulnerable endpoint path
• Deploy intrusion detection signatures to identify exploitation attempts against D-Link router management interfaces
• Use SentinelOne Singularity XDR to monitor for lateral movement following potential information disclosure from network devices

Monitoring Recommendations

• Enable verbose logging on affected D-Link routers if available
• Monitor network traffic to and from router management interfaces
• Set up alerts for access attempts to router configuration endpoints from non-administrative networks
• Regularly audit devices connected to your network for end-of-life equipment

How to Mitigate CVE-2026-2056

Immediate Actions Required

• Replace affected D-Link DIR-605L and DIR-619L routers with currently supported models
• If immediate replacement is not possible, restrict management interface access to trusted internal networks only
• Disable remote administration features on affected devices
• Implement network segmentation to isolate vulnerable devices from critical systems

Patch Information

This vulnerability affects products that are no longer supported by D-Link. No security patch will be released for the affected firmware versions (2.06B01 and 2.13B01). D-Link recommends replacing these end-of-life devices with current models that receive ongoing security support. For more information, visit the D-Link Official Website.

Additional vulnerability tracking information is available at VulDB #344616.

Workarounds

• Configure firewall rules to block external access to the router's web management interface on port 80/443
• Use access control lists (ACLs) to restrict management interface access to specific trusted IP addresses
• Place the vulnerable router behind a more secure network device that can filter malicious requests
• Consider using VPN-only access for router management if remote administration is required

# Example iptables rules to restrict router management access
# Run these on a perimeter firewall protecting the vulnerable device
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 80 -j DROP
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 443 -j DROP
# Allow management only from trusted admin subnet
iptables -A FORWARD -s 192.168.1.0/24 -d <ROUTER_IP> -p tcp --dport 80 -j ACCEPT