CVE-2025-71383: Dbit WIFI4 N300 DoS Vulnerability

CVE-2025-71383 Overview

CVE-2025-71383 affects Dbit WIFI4 N300 1.0.0 devices and allows an attacker on the local Wi-Fi network to crash the device management interface. The flaw stems from an error in the JSON parser that handles authentication requests. An attacker triggers the crash by sending a request to the /api/login endpoint that omits the username or password field. No credentials are required to reproduce the condition.

Critical Impact
An unauthenticated attacker on the local wireless network can disable the router's management interface by sending a single malformed JSON login request, interrupting administrative access.

Affected Products

Dbit WIFI4 N300 router, firmware version 1.0.0
Management web interface exposed on the local Wi-Fi network
The /api/login endpoint handling JSON authentication payloads

Discovery Timeline

2026-10-06 - CVE-2025-71383 published to the National Vulnerability Database (NVD)
2026-10-06 - Last updated in NVD database

Technical Details for CVE-2025-71383

Vulnerability Analysis

The vulnerability is a denial-of-service condition in the authentication path of the Dbit WIFI4 N300 management interface. When the device receives an HTTP POST request to /api/login, it passes the request body to a JSON parser that expects both username and password fields. If either field is missing, the parser fails in a way that terminates the management service rather than returning a controlled error response.

The result is loss of availability for the administrative interface. Legitimate administrators cannot authenticate, view status pages, or change configuration until the service recovers or the device is rebooted. Repeated requests can keep the interface offline. The condition is reachable by any client associated with the local Wi-Fi network, including guest clients where network segmentation is weak.

Further technical context on the broader exploit chain affecting this device family is available in the Klogix Security Scorpion Labs analysis.

Root Cause

The root cause is improper input validation in the JSON parser used by the login handler. The parser assumes required fields are present and does not safely handle requests that omit them. This is an input validation and denial-of-service defect in the embedded web management component.

Attack Vector

The attack vector is adjacent-network. An attacker must be associated with the device's Wi-Fi network but does not need valid credentials. Exploitation consists of sending a crafted HTTP POST request to /api/login with a JSON body that is missing the username field, the password field, or both. The malformed request causes the parser error that crashes the management interface.

No verified proof-of-concept code is published for CVE-2025-71383. The vulnerability is described in prose in the referenced advisory; readers should consult the Klogix Security write-up linked above for additional detail on request structure.

Detection Methods for CVE-2025-71383

Indicators of Compromise

Unexpected restarts or unresponsiveness of the Dbit WIFI4 N300 management web interface.
HTTP POST requests to /api/login with JSON bodies missing the username or password field.
Repeated authentication requests from a single wireless client immediately preceding management interface downtime.

Detection Strategies

Inspect router logs for parser errors or service restarts correlated with requests to /api/login.
Monitor wireless client traffic for malformed JSON payloads targeting management endpoints.
Alert on health checks that report the management interface as unreachable while the device remains online for client traffic.

Monitoring Recommendations

Track availability of the device management interface with an external uptime probe that performs a benign GET request.
Where available, forward syslog from the device to a central collector and alert on authentication subsystem crashes.
Review DHCP and Wi-Fi association logs to identify unknown clients that appeared immediately before management interface outages.

How to Mitigate CVE-2025-71383

Immediate Actions Required

Restrict access to the Wi-Fi network using strong WPA2 or WPA3 credentials to reduce the attacker population.
Disable guest network access to the management subnet, or isolate guest clients from the router's management IP.
Reboot the device to restore the management interface if it becomes unresponsive, and investigate the source client.

Patch Information

No vendor patch is referenced in the NVD entry for CVE-2025-71383 at the time of publication. Administrators should monitor Dbit communications for a firmware update addressing the JSON parser error in the /api/login handler and apply it when released.

Workarounds

Block client-to-management-interface traffic using access control lists on the router where supported.
Place the Dbit WIFI4 N300 on an isolated SSID limited to trusted administrative devices only.
Consider replacing the device in high-availability environments where a management-interface DoS is unacceptable.

bash

# Example: isolate wireless clients from the router management IP using iptables
# (apply on an upstream Linux gateway, not on the Dbit device itself)
MGMT_IP="192.168.1.1"
WIFI_IF="wlan0"

iptables -I FORWARD -i ${WIFI_IF} -d ${MGMT_IP} -p tcp --dport 80 -j DROP
iptables -I FORWARD -i ${WIFI_IF} -d ${MGMT_IP} -p tcp --dport 443 -j DROP