CVE-2025-4141: Netgear EX6200 Buffer Overflow Vulnerability

CVE-2025-4141 Overview

CVE-2025-4141 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_3C03C function within the bpa_server component. Attackers can manipulate the host argument to trigger a memory corruption condition. The vulnerability is remotely exploitable over the network and affects both confidentiality and integrity of the device. According to VulDB, the vendor was contacted but did not respond to the disclosure. The weakness is classified under [CWE-119] and [CWE-120], covering improper restriction of operations within memory buffer bounds.

Critical Impact
Remote attackers with low privileges can overflow a memory buffer in the Netgear EX6200 bpa_server, potentially leading to arbitrary code execution or device compromise.

Affected Products

Netgear EX6200 hardware device
Netgear EX6200 firmware version 1.0.3.94
The sub_3C03C function in the bpa_server binary

Discovery Timeline

2025-04-30 - CVE-2025-4141 published to the National Vulnerability Database
2025-05-12 - Last updated in the NVD database

Technical Details for CVE-2025-4141

Vulnerability Analysis

The vulnerability exists in the sub_3C03C function inside the bpa_server binary shipped with Netgear EX6200 firmware 1.0.3.94. The function processes the host argument without enforcing length validation before copying it into a fixed-size buffer. This unchecked copy operation causes adjacent memory regions to be overwritten when an oversized value is supplied. The result is a classic buffer overflow condition mapped to [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer) and [CWE-120] (Buffer Copy without Checking Size of Input).

An attacker reaching the device over the network can submit a crafted request that triggers the unsafe copy. Successful exploitation can corrupt control data on the stack or heap, depending on the buffer location, and may lead to arbitrary code execution on the underlying embedded Linux system. The EPSS score of 1.243% places this vulnerability in the 79th percentile for likely exploitation activity.

Root Cause

The root cause is missing bounds checking on attacker-controlled input. The sub_3C03C function trusts the length of the host parameter and copies it into a fixed-size stack or heap buffer. No validation against the destination buffer size occurs before the write.

Attack Vector

The attack vector is network-based and requires low privileges to reach the vulnerable service. No user interaction is required. An attacker who can send requests to the bpa_server interface on the EX6200 can deliver an oversized host argument to trigger the overflow.

No verified proof-of-concept code is reproduced here. Technical details are available in the GitHub PoC Repository and the VulDB Entry #306633.

Detection Methods for CVE-2025-4141

Indicators of Compromise

Unexpected restarts or crash logs of the bpa_server process on the EX6200
Inbound network requests to the EX6200 management interface containing abnormally long host parameter values
Configuration changes or new administrative sessions on the device that are not attributable to authorized users
Outbound connections from the extender to unfamiliar IP addresses or domains

Detection Strategies

Inspect HTTP and management traffic destined for EX6200 devices for oversized header or parameter values, particularly the host field
Monitor for repeated connection failures or service restarts on the extender, which can indicate exploitation attempts against sub_3C03C
Capture device syslog output where available and alert on segmentation faults or process termination events tied to bpa_server

Monitoring Recommendations

Isolate the EX6200 management interface on a dedicated VLAN and apply IDS or IPS signatures for buffer overflow patterns targeting embedded HTTP services
Forward network telemetry from the segment hosting the EX6200 to a centralized analytics platform for anomaly detection
Track firmware version inventory across the environment to identify devices still running 1.0.3.94

How to Mitigate CVE-2025-4141

Immediate Actions Required

Remove the Netgear EX6200 from any network segment exposed to untrusted clients until a fix is available
Restrict access to the device management interface to a trusted administrative subnet only
Disable remote administration features on the EX6200 if they are enabled
Audit existing device configurations for unauthorized changes that may indicate prior exploitation

Patch Information

No vendor patch has been published. According to the disclosure, Netgear was contacted but did not respond. Administrators should monitor the Netgear Official Website for future firmware updates addressing the sub_3C03C buffer overflow in bpa_server.

Workarounds

Replace the EX6200 with a supported model that receives active security maintenance
Place the extender behind a firewall that blocks inbound access to its management services from untrusted networks
Enforce network segmentation so that compromise of the extender cannot pivot into internal corporate or sensitive segments
Disable the bpa_server service if administrative controls allow doing so without breaking required functionality

bash

# Example firewall rule restricting EX6200 management access to a trusted admin subnet
iptables -A FORWARD -s 10.10.20.0/24 -d 192.168.1.250 -p tcp --dport 80 -j ACCEPT
iptables -A FORWARD -d 192.168.1.250 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.1.250 -p tcp --dport 443 -j DROP