CVE-2025-71384: Dbit WIFI4 N300 Buffer Overflow Vulnerability

CVE-2025-71384 Overview

CVE-2025-71384 affects Dbit WIFI4 N300 1.0.0 devices. The flaw allows authenticated administrators on the local Wi-Fi network to execute operating system commands by triggering a stack-based buffer overflow. The overflow occurs through the comment field of the /api/addStaticDHCP endpoint. Successful exploitation yields remote code execution on the router with elevated privileges.

The vulnerability is tracked under CWE-121: Stack-based Buffer Overflow. It requires local network adjacency and administrative credentials, limiting broad internet-based exploitation.

Critical Impact
Authenticated attackers on the local Wi-Fi can achieve arbitrary command execution on the router, enabling full device takeover, traffic interception, and lateral movement into connected networks.

Affected Products

Dbit WIFI4 N300 router, firmware version 1.0.0
Device administration web interface exposing /api/addStaticDHCP
Deployments where attackers can authenticate to the local Wi-Fi management console

Discovery Timeline

2026-10-06 - CVE-2025-71384 published to the National Vulnerability Database
2026-10-07 - Last updated in NVD database

Technical Details for CVE-2025-71384

Vulnerability Analysis

The Dbit WIFI4 N300 router exposes an administrative REST endpoint, /api/addStaticDHCP, used to assign static DHCP leases. The handler accepts a user-controlled comment string and copies it into a fixed-size stack buffer without validating length. Supplying an oversized value corrupts the saved return address and adjacent stack frames.

Because the router firmware runs the web management service with elevated privileges and lacks modern memory protections typical of embedded Linux targets, the overflow can be weaponized into command execution. The attacker needs valid administrator credentials and local network reachability to the device management interface. According to the Klogix Security blog analysis, the chain demonstrates how administrative input fields in consumer IoT devices translate directly to RCE when sanitization is absent.

Root Cause

The root cause is missing bounds checking on the comment parameter in the /api/addStaticDHCP handler. The code likely uses an unsafe string copy routine such as strcpy or sprintf into a fixed-length stack buffer. Length validation and safer alternatives like strncpy with explicit size enforcement would prevent the overflow.

Attack Vector

Exploitation requires network access to the router's administrative interface and valid high-privilege credentials. An attacker sends an HTTP POST request to /api/addStaticDHCP containing an overlong comment value crafted to overwrite the return address with a payload or ROP chain. Once the function returns, control transfers to attacker-chosen code, allowing OS command execution as the web service user.

For exploitation details, see the Klogix Security Scorpion Labs analysis.

Detection Methods for CVE-2025-71384

Indicators of Compromise

Oversized or binary-laden comment field values recorded in /api/addStaticDHCP request logs
Unexpected restarts, segmentation faults, or watchdog resets of the router management daemon
New or modified static DHCP entries that do not correlate with legitimate administrative activity
Outbound connections from the router to unknown IP addresses or shell listeners

Detection Strategies

Inspect HTTP POST bodies to /api/addStaticDHCP for non-printable bytes or comment values exceeding typical lengths (for example, more than 128 bytes)
Enable syslog forwarding from the router and alert on repeated authentication failures followed by configuration changes
Correlate administrative logins with subsequent unusual process activity or network flows originating from the router

Monitoring Recommendations

Forward router logs to a centralized logging platform for retention and query
Baseline normal administrator activity windows and alert on off-hours configuration API calls
Monitor the local management VLAN for new TCP listeners or reverse-shell patterns originating from the router

How to Mitigate CVE-2025-71384

Immediate Actions Required

Restrict access to the router's administrative interface to a dedicated management VLAN or trusted hosts only
Rotate all administrator credentials and enforce strong, unique passwords
Disable remote and wireless administration where feasible; require wired access for configuration changes
Audit existing static DHCP entries and remove any unrecognized reservations

Patch Information

No vendor advisory or firmware update is listed in the NVD record at the time of publication. Monitor the Dbit vendor channels and the Klogix Security Scorpion Labs blog for remediation guidance. If no patch becomes available, consider replacing the affected device.

Workarounds

Place the router behind a segmented network and block administrative API access from general-purpose Wi-Fi clients
Enforce administrative access only through MAC-filtered or 802.1X-authenticated management SSIDs
Limit the number of personnel with administrative credentials and log every configuration change
Deploy an upstream firewall rule to drop traffic destined for /api/addStaticDHCP from untrusted subnets

bash

# Example: restrict access to router management interface using iptables upstream
iptables -A FORWARD -p tcp -d 192.0.2.1 --dport 80 -s 10.10.10.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d 192.0.2.1 --dport 80 -j DROP
iptables -A FORWARD -p tcp -d 192.0.2.1 --dport 443 -s 10.10.10.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d 192.0.2.1 --dport 443 -j DROP