CVE-2025-4115: Netgear JWNR2000 Buffer Overflow Vulnerability

CVE-2025-4115 Overview

A critical buffer overflow vulnerability has been identified in the Netgear JWNR2000v2 wireless router firmware version 1.0.0.11. This vulnerability affects the default_version_is_new function where manipulation of the host argument can lead to a buffer overflow condition. The vulnerability is remotely exploitable over the network, allowing attackers to potentially compromise affected devices without physical access.

Critical Impact

Remote attackers can exploit this buffer overflow vulnerability to potentially execute arbitrary code or cause denial of service on affected Netgear JWNR2000v2 routers, compromising network security and potentially enabling further attacks on connected devices.

Affected Products

• Netgear JWNR2000v2 Router Hardware
• Netgear JWNR2000 Firmware version 1.0.0.11
• Netgear JWNR2000 Firmware (all versions prior to patch availability)

Discovery Timeline

• 2025-04-30 - CVE-2025-4115 published to NVD
• 2025-05-16 - Last updated in NVD database

Technical Details for CVE-2025-4115

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-120 (Buffer Copy without Checking Size of Input). The vulnerable function default_version_is_new fails to properly validate the size of the host argument before copying it to a fixed-size buffer. This classic buffer overflow condition allows an attacker to write data beyond the allocated memory boundaries.

The vulnerability can be exploited remotely over the network without user interaction, though it requires low-level privileges. Successful exploitation could lead to complete compromise of the router's confidentiality, integrity, and availability. Given the router's position as a network gateway device, compromise could facilitate further attacks on the internal network.

The vendor, Netgear, was contacted about this disclosure but did not respond, leaving users without an official patch. Technical details and proof-of-concept information have been documented in publicly available security research.

Root Cause

The root cause of this vulnerability lies in the default_version_is_new function's failure to implement proper bounds checking when processing the host argument. The function copies user-supplied input into a fixed-size buffer without verifying that the input length does not exceed the buffer's capacity. This is a classic example of CWE-120 (Buffer Copy without Checking Size of Input), where unsafe memory operations allow attackers to overwrite adjacent memory regions.

Attack Vector

The attack can be launched remotely over the network by sending a specially crafted request containing an oversized host parameter to the vulnerable default_version_is_new function. The attacker does not require physical access to the device and exploitation does not require user interaction.

An attacker would craft a malicious request with an excessively long host value designed to overflow the target buffer. By carefully constructing the overflow payload, the attacker could potentially overwrite return addresses or function pointers to redirect execution flow to attacker-controlled code. For detailed technical analysis and proof-of-concept information, refer to the GitHub PoC Repository.

Detection Methods for CVE-2025-4115

Indicators of Compromise

• Unexpected router reboots or instability that could indicate exploitation attempts
• Anomalous network traffic patterns targeting the router's management interface
• Unusually long HTTP request parameters in router access logs, particularly in the host field
• Unexpected changes to router configuration or firmware

Detection Strategies

• Monitor network traffic for oversized HTTP requests targeting Netgear JWNR2000v2 management interfaces
• Implement network intrusion detection rules to identify buffer overflow attack patterns against embedded devices
• Deploy network segmentation to isolate router management interfaces from untrusted network segments
• Review router logs for suspicious access attempts or malformed requests

Monitoring Recommendations

• Enable logging on the router's management interface and regularly review access logs
• Implement network-level monitoring to detect anomalous traffic patterns to router IP addresses
• Consider deploying a network intrusion detection system (NIDS) to monitor traffic destined for network infrastructure devices
• Set up alerts for unusual router behavior such as unexpected restarts or configuration changes

How to Mitigate CVE-2025-4115

Immediate Actions Required

• Restrict access to the router's management interface to trusted IP addresses only
• Disable remote management if not required for operations
• Place the router's management interface on a separate VLAN with strict access controls
• Consider replacing the affected device with a supported model if no patch becomes available
• Monitor for unusual network activity targeting the router

Patch Information

At the time of publication, Netgear has not released a security patch for this vulnerability. The vendor was contacted about this disclosure but did not respond. Users should monitor the Netgear Official Website for any future security advisories. Given the lack of vendor response, users should consider implementing workarounds and evaluating device replacement with actively supported hardware.

Additional technical details are available in the VulDB entry #306595.

Workarounds

• Disable remote management access to the router from WAN interfaces
• Implement firewall rules to restrict access to the router's management interface to specific trusted IP addresses
• Enable strong authentication for router administration and use non-default credentials
• Consider deploying the router behind an additional firewall or security appliance that can filter malicious traffic
• Evaluate replacement of the JWNR2000v2 with a currently supported router model that receives security updates

# Example: Restrict management access via firewall rules (applied on upstream firewall)
# Block external access to router management ports
iptables -A FORWARD -d ROUTER_IP -p tcp --dport 80 -j DROP
iptables -A FORWARD -d ROUTER_IP -p tcp --dport 443 -j DROP
# Allow only trusted management IP
iptables -A FORWARD -s TRUSTED_ADMIN_IP -d ROUTER_IP -p tcp --dport 80 -j ACCEPT