CVE-2025-4149: Netgear EX6200 Buffer Overflow Vulnerability

CVE-2025-4149 Overview

CVE-2025-4149 is a buffer overflow vulnerability in the Netgear EX6200 WiFi range extender running firmware version 1.0.3.94. The flaw resides in the sub_54014 function, where manipulation of the host argument triggers a memory corruption condition. The vulnerability is remotely exploitable over the network and requires low privileges to abuse. The vendor was contacted before public disclosure but did not respond. The issue is tracked under [CWE-119] and [CWE-120], covering improper restriction of operations within memory buffer bounds.

Critical Impact
Remote attackers with low privileges can corrupt memory on affected Netgear EX6200 devices, potentially achieving arbitrary code execution and full compromise of the network extender.

Affected Products

Netgear EX6200 WiFi Range Extender (hardware)
Netgear EX6200 Firmware version 1.0.3.94
Internal function sub_54014 processing the host parameter

Discovery Timeline

2025-05-01 - CVE-2025-4149 published to the National Vulnerability Database (NVD)
2025-05-19 - Last updated in NVD database

Technical Details for CVE-2025-4149

Vulnerability Analysis

The vulnerability is a classic buffer overflow within the sub_54014 function of the Netgear EX6200 firmware. The function processes the host argument without enforcing proper length validation before copying data into a fixed-size buffer. An attacker who can send a crafted request to the device's web management interface can supply an oversized host value, overflowing adjacent memory regions.

Successful exploitation can corrupt return addresses or function pointers on the stack, redirecting execution flow. On embedded MIPS or ARM-based Netgear devices, this typically leads to arbitrary code execution under the privileges of the web management daemon, which commonly runs as root.

Public proof-of-concept material is referenced through the GitHub Buffer Overflow PoC and VulDB entry #306681. The EPSS probability of exploitation is approximately 0.55%.

Root Cause

The root cause is insufficient bounds checking in sub_54014 when handling the user-controlled host argument. The function trusts the size of attacker-supplied input and performs an unbounded copy into a fixed-size stack or heap buffer, classified as [CWE-119] and [CWE-120].

Attack Vector

The attack vector is network-based and requires low-level authenticated access to the device's management interface. An attacker sends a specially crafted HTTP request containing an oversized host parameter, triggering the overflow inside sub_54014. No user interaction is required, and the attack can be automated against exposed devices.

No synthetic exploitation code is provided. See the GitHub Buffer Overflow PoC for technical reproduction details.

Detection Methods for CVE-2025-4149

Indicators of Compromise

Unusually long host header or parameter values in HTTP requests sent to the EX6200 management interface.
Unexpected reboots, crashes, or service restarts of the device's web administration daemon.
Outbound connections from the extender to unfamiliar IP addresses, suggesting post-exploitation command-and-control.
New or modified firmware components inconsistent with the installed 1.0.3.94 baseline.

Detection Strategies

Inspect HTTP traffic destined for the EX6200 administration interface for oversized parameter values, particularly host.
Apply intrusion detection signatures that flag malformed or excessively long parameters against known embedded web servers.
Correlate device crash logs with inbound network requests to identify exploitation attempts.

Monitoring Recommendations

Restrict and log all access to the EX6200 web management interface, alerting on access from non-administrative subnets.
Monitor for repeated connection resets or 5xx errors from the device's HTTP service, which can indicate overflow attempts.
Forward firewall and IDS telemetry to a centralized analytics platform to baseline normal management traffic and surface anomalies.

How to Mitigate CVE-2025-4149

Immediate Actions Required

Remove EX6200 devices running firmware 1.0.3.94 from any internet-exposed segment until a patch is available.
Restrict access to the device's web management interface to a dedicated administrative VLAN with explicit allow-listing.
Disable remote management features on the EX6200 if they are not strictly required.
Audit existing devices for signs of compromise, including unexpected configuration changes or unknown administrative sessions.

Patch Information

As of the last NVD update on 2025-05-19, Netgear has not issued a vendor advisory or patched firmware for CVE-2025-4149. The vendor did not respond to coordinated disclosure attempts. Administrators should monitor the Netgear support site for future firmware updates addressing the sub_54014 buffer overflow.

Workarounds

Place the EX6200 behind a network firewall that blocks untrusted access to its HTTP and HTTPS management ports.
Consider replacing the EX6200 with a supported device if Netgear does not release a fix, particularly in environments with strict security requirements.
Segment IoT and consumer-grade network equipment away from production assets to limit lateral movement after compromise.

bash

# Configuration example: restrict management access using iptables on an upstream gateway
iptables -A FORWARD -p tcp -d <EX6200_IP> --dport 80 -s <ADMIN_SUBNET> -j ACCEPT
iptables -A FORWARD -p tcp -d <EX6200_IP> --dport 80 -j DROP
iptables -A FORWARD -p tcp -d <EX6200_IP> --dport 443 -s <ADMIN_SUBNET> -j ACCEPT
iptables -A FORWARD -p tcp -d <EX6200_IP> --dport 443 -j DROP