CVE-2025-53756 Overview
CVE-2025-53756 affects the Digisol DG-GR6821AC Router. The web management interface transmits user credentials in cleartext over the network. A remote attacker positioned to intercept traffic between an administrator and the router can capture these credentials without decryption. Successful exploitation grants unauthorized administrative access to the device.
The weakness maps to [CWE-319]: Cleartext Transmission of Sensitive Information. India's Computer Emergency Response Team (CERT-In) published the issue under advisory CIVN-2025-0147. No vendor patch reference is listed in the public CVE record at the time of writing.
Critical Impact
Network-adjacent attackers can capture administrator credentials in plaintext from router management traffic, leading to full device takeover.
Affected Products
- Digisol DG-GR6821AC Router
- Web management interface component
- Firmware versions identified in CERT-In Vulnerability Note CIVN-2025-0147
Discovery Timeline
- 2025-07-16 - CVE-2025-53756 published to NVD
- 2026-04-15 - Last updated in NVD database
Technical Details for CVE-2025-53756
Vulnerability Analysis
The Digisol DG-GR6821AC Router exposes a web management interface for administrative configuration. This interface accepts login credentials over an unencrypted channel. Credentials traverse the network without Transport Layer Security (TLS) protection. Any attacker with access to a network segment between the administrator and the router can read the authentication payload directly.
The vulnerability is exploitable remotely across the network and requires no authentication or user interaction. Common attack positions include a compromised LAN host, a rogue Wi-Fi access point, or an upstream network device under attacker control. Once credentials are captured, the attacker authenticates to the web interface as a legitimate administrator.
Full administrative access allows changes to routing, DNS, firewall rules, port forwarding, and firmware. Attackers commonly redirect DNS to malicious resolvers, open inbound paths to internal hosts, or stage further intrusions against connected clients.
Root Cause
The root cause is the absence of encrypted transport on the management interface. The router serves administrative pages over HTTP rather than HTTPS, or accepts credential submissions over an unprotected channel. Authentication data is therefore visible to any party with packet-capture capability on the path.
Attack Vector
The attack vector is network-based and passive in its simplest form. An attacker runs a packet capture tool such as tcpdump or Wireshark on a position between the administrator and the router. Captured HTTP POST requests to the login endpoint expose the username and password fields directly. Active variants include ARP spoofing on the LAN to force traffic through the attacker host.
No verified public exploit code is referenced in the enriched data. See CERT-In Vulnerability Note CIVN-2025-0147 for vendor-coordinated technical details.
Detection Methods for CVE-2025-53756
Indicators of Compromise
- Unexpected administrator logins to the router web interface from unfamiliar source addresses.
- Configuration changes to DNS, firewall, or port-forwarding rules without authorized change records.
- ARP table anomalies on the management LAN indicating spoofing activity.
- Outbound HTTP traffic on TCP/80 containing credential form fields directed to the router IP.
Detection Strategies
- Inspect network captures between administrator workstations and the router for cleartext HTTP authentication to the device management IP.
- Alert on any HTTP POST to router login endpoints when HTTPS is expected for management traffic.
- Correlate router configuration changes with authenticated administrator sessions to flag unauthorized modifications.
Monitoring Recommendations
- Log and review all access to the router management interface from a centralized syslog collector.
- Monitor DHCP and ARP activity on the management VLAN for spoofing patterns that precede credential capture.
- Track firmware version and configuration baselines and alert on deviations.
How to Mitigate CVE-2025-53756
Immediate Actions Required
- Restrict access to the router web management interface to a dedicated management VLAN or specific administrator hosts.
- Disable remote (WAN-side) management on the DG-GR6821AC until a vendor patch is confirmed applied.
- Rotate administrator credentials and avoid reusing passwords across other network devices.
- Administer the device only from a trusted, wired connection to reduce exposure to wireless interception.
Patch Information
No vendor patch URL is listed in the enriched CVE data. Consult CERT-In Vulnerability Note CIVN-2025-0147 for vendor coordination status and any firmware updates released by Digisol. Apply firmware updates that introduce HTTPS-only management as soon as they are available.
Workarounds
- Place the router management interface behind an out-of-band management network not reachable from user subnets.
- Tunnel administrative sessions through an encrypted channel such as an SSH or VPN jump host before reaching the router.
- Segment the LAN to prevent untrusted hosts from sharing a broadcast domain with the router management address.
- Enforce strict access control lists on switches to block unauthorized hosts from communicating with the router management IP.
# Example: restrict router admin interface to a single management host using an upstream firewall
# Replace 192.0.2.10 with the authorized administrator host and 192.0.2.1 with the router IP
iptables -A FORWARD -s 192.0.2.10 -d 192.0.2.1 -p tcp --dport 80 -j ACCEPT
iptables -A FORWARD -d 192.0.2.1 -p tcp --dport 80 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
