CVE-2025-4117: Netgear JWNR2000 Buffer Overflow Vulnerability

CVE-2025-4117 Overview

A critical buffer overflow vulnerability has been identified in the Netgear JWNR2000v2 wireless router running firmware version 1.0.0.11. The vulnerability exists within the sub_41A914 function, where improper handling of the host argument allows an attacker to trigger a buffer overflow condition. This flaw could enable an authenticated attacker on an adjacent network to compromise the confidentiality, integrity, and availability of the affected device. Notably, the vendor was contacted about this disclosure but did not respond.

Critical Impact

Buffer overflow in Netgear JWNR2000v2 router firmware allows adjacent network attackers to potentially execute arbitrary code or cause denial of service through manipulation of the host parameter.

Affected Products

• Netgear JWNR2000v2 Firmware version 1.0.0.11
• Netgear JWNR2000 Hardware version v2

Discovery Timeline

• 2025-04-30 - CVE-2025-4117 published to NVD
• 2025-05-16 - Last updated in NVD database

Technical Details for CVE-2025-4117

Vulnerability Analysis

This buffer overflow vulnerability (CWE-119, CWE-120) affects the Netgear JWNR2000v2 router's firmware at function sub_41A914. The vulnerability is exploitable from an adjacent network, requiring low attack complexity and low privileges. No user interaction is required for exploitation.

The attack requires the adversary to be on the same local network segment as the vulnerable router, which somewhat limits the attack surface but still poses significant risk in shared network environments such as offices, hotels, or public WiFi deployments where multiple users connect to the same network infrastructure.

Root Cause

The root cause of this vulnerability is a classic buffer overflow condition (CWE-120: Buffer Copy without Checking Size of Input) within the sub_41A914 function. The function fails to properly validate the size of user-supplied input in the host argument before copying it into a fixed-size buffer. This allows an attacker to provide oversized input that exceeds the buffer boundaries, potentially overwriting adjacent memory locations including return addresses or function pointers.

Attack Vector

The attack vector requires adjacent network access (AV:A), meaning the attacker must be on the same network segment as the target device. The attack has low complexity (AC:L) and requires low privileges (PR:L), but no user interaction is needed. An attacker could craft a malicious request containing an oversized host parameter value to trigger the buffer overflow condition.

The vulnerability affects the router's web management interface or associated network services that process the host argument. Successful exploitation could allow the attacker to corrupt memory, crash the device, or potentially achieve code execution depending on the specific memory layout and available exploitation primitives.

For detailed technical analysis and proof-of-concept information, refer to the GitHub PoC for Netgear Router.

Detection Methods for CVE-2025-4117

Indicators of Compromise

• Unusual or malformed HTTP requests targeting the router's web management interface with oversized host parameter values
• Unexpected router crashes, reboots, or service disruptions that may indicate exploitation attempts
• Anomalous network traffic patterns from the router's IP address suggesting compromised device behavior

Detection Strategies

• Deploy network intrusion detection systems (IDS) to monitor for abnormally large or malformed requests to the router's management interface
• Implement network segmentation to isolate management interfaces and limit exposure to adjacent network attacks
• Monitor router logs for authentication anomalies or repeated access attempts from unexpected sources

Monitoring Recommendations

• Enable and regularly review router access logs for suspicious activity patterns
• Configure network monitoring tools to alert on unusual traffic volumes or patterns involving the affected router
• Implement periodic firmware version audits to identify vulnerable devices in your environment

How to Mitigate CVE-2025-4117

Immediate Actions Required

• Restrict access to the router's management interface to trusted hosts only using access control lists (ACLs)
• Disable remote management features if not required for operations
• Segment the network to limit adjacent network access to critical infrastructure devices
• Consider replacing affected devices with supported hardware that receives regular security updates

Patch Information

No patch is currently available for this vulnerability. According to the disclosure, the vendor (Netgear) was contacted about this vulnerability but did not respond. The Netgear JWNR2000v2 is an older router model that may have reached end-of-life status and may not receive firmware updates.

Organizations using this hardware should strongly consider migrating to newer, actively supported router models. Check the Netgear Official Website for any future security advisories or firmware updates.

Workarounds

• Implement strict network access controls to limit which devices can communicate with the router on the local network
• Place the router behind a firewall that filters and inspects traffic destined for the management interface
• Disable unnecessary services and features on the router to reduce the attack surface
• Use VPN or other secure access methods for administrative functions rather than direct web interface access

# Network segmentation example using iptables on a gateway device
# Restrict access to router management interface (192.168.1.1) from specific trusted hosts only

# Drop all traffic to router management port from untrusted sources
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP

# Allow only from specific management workstation (192.168.1.100)
iptables -I FORWARD -s 192.168.1.100 -d 192.168.1.1 -p tcp --dport 80 -j ACCEPT
iptables -I FORWARD -s 192.168.1.100 -d 192.168.1.1 -p tcp --dport 443 -j ACCEPT