CVE-2025-4114 Overview
CVE-2025-4114 is a buffer overflow vulnerability in the Netgear JWNR2000v2 wireless router running firmware version 1.0.0.11. The flaw resides in the check_language_file function, where manipulation of the host argument triggers memory corruption [CWE-119, CWE-120]. An attacker can exploit the issue remotely over the network with low privileges and no user interaction. According to public records, the vendor was contacted prior to disclosure but did not respond, and no patch is currently available. The JWNR2000v2 is an end-of-life consumer router, which increases long-term exposure for users still operating the device.
Critical Impact
Remote attackers with low privileges can trigger a buffer overflow in check_language_file, potentially leading to arbitrary code execution or denial of service on affected Netgear JWNR2000v2 routers.
Affected Products
- Netgear JWNR2000v2 hardware revision v2
- Netgear JWNR2000 firmware version 1.0.0.11
- End-of-life consumer wireless routers from Netgear running the vulnerable firmware build
Discovery Timeline
- 2025-04-30 - CVE-2025-4114 published to the National Vulnerability Database
- 2025-05-28 - Last updated in NVD database
Technical Details for CVE-2025-4114
Vulnerability Analysis
The vulnerability exists in the check_language_file function within the JWNR2000v2 web management interface. The function processes the host HTTP header argument without enforcing proper bounds checking on the input length. When an attacker submits an overly long value, the data overflows a fixed-size buffer in adjacent memory.
Buffer overflows in embedded router firmware typically allow attackers to overwrite saved return addresses or function pointers on the stack. Successful exploitation can yield arbitrary code execution in the context of the web server process, which on consumer-grade routers commonly runs with elevated privileges. A failed exploitation attempt usually crashes the HTTP daemon, producing a denial of service condition on the device.
The attack vector is network-based and requires only low privileges. Because the device is end-of-life and the vendor did not respond to disclosure, no official fix is expected.
Root Cause
The root cause is missing input validation on the host parameter passed to check_language_file. The function copies attacker-controlled data into a stack or heap buffer using an unsafe string operation that does not validate the destination buffer size, classified under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer) and [CWE-120] (Classic Buffer Overflow).
Attack Vector
An attacker sends a crafted HTTP request containing an oversized host argument to the router's management interface. If the interface is reachable from the WAN or a hostile LAN segment, the overflow triggers without user interaction. Technical details and proof-of-concept material are published in the GitHub PoC Repository and indexed in VulDB #306594.
No verified exploit code is reproduced here. Refer to the linked references for technical reproduction details.
Detection Methods for CVE-2025-4114
Indicators of Compromise
- HTTP requests to the JWNR2000v2 management interface containing abnormally long Host headers or host parameter values
- Unexpected reboots or repeated crashes of the router's web administration service
- Outbound connections from the router to unknown infrastructure, indicating post-exploitation persistence
- Configuration changes such as modified DNS servers, new administrative accounts, or altered firewall rules
Detection Strategies
- Inspect network traffic for HTTP requests targeting router management URLs with host parameter values exceeding typical hostname lengths
- Monitor router system logs and SNMP traps for repeated HTTP daemon restarts or segmentation faults
- Use network discovery to inventory JWNR2000v2 devices and confirm firmware version 1.0.0.11 exposure
Monitoring Recommendations
- Forward router syslog output to a centralized logging platform and alert on web service crash patterns
- Baseline DNS resolver settings on perimeter devices and alert on unauthorized changes
- Monitor for management interface access originating from WAN addresses or non-administrative subnets
How to Mitigate CVE-2025-4114
Immediate Actions Required
- Disable remote (WAN-side) administration on the JWNR2000v2 if currently enabled
- Restrict LAN access to the router management interface to a dedicated administrative VLAN or host
- Replace end-of-life JWNR2000v2 hardware with a currently supported router model, as the vendor has not responded to disclosure
- Change administrative credentials and audit DNS, firewall, and port-forwarding settings for unauthorized modifications
Patch Information
No official patch is available. The Netgear Official Website does not list a security advisory for this issue, and the JWNR2000v2 is an end-of-life product. Affected users should treat device replacement as the primary remediation path.
Workarounds
- Place the router behind an upstream firewall that filters inbound HTTP and HTTPS traffic to the management interface
- Apply MAC or IP-based access control lists to limit who can reach the administrative web UI
- Segment the router's management plane from untrusted wired and wireless clients
- Disable UPnP and any unused services that expose additional network attack surface
# Example: block external access to router management on an upstream firewall (iptables)
iptables -A FORWARD -p tcp -d <router_lan_ip> --dport 80 -s ! <admin_subnet> -j DROP
iptables -A FORWARD -p tcp -d <router_lan_ip> --dport 443 -s ! <admin_subnet> -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
