CVE-2025-6565: Netgear WNCE3001 Buffer Overflow Flaw

CVE-2025-6565 Overview

CVE-2025-6565 is a stack-based buffer overflow in the Netgear WNCE3001 wireless range extender running firmware version 1.0.0.50. The flaw resides in the http_d function within the HTTP POST request handler. Attackers manipulate the Host header to overflow a fixed-size stack buffer, corrupting saved return addresses and adjacent stack data. The issue is remotely exploitable over the network and requires only low-privilege access to the device's HTTP service. Public proof-of-concept code has been disclosed, increasing the likelihood of opportunistic exploitation against exposed extenders. The vulnerability is categorized under CWE-119, improper restriction of operations within the bounds of a memory buffer.

Critical Impact

Remote attackers can corrupt stack memory in the WNCE3001 HTTP daemon by sending a crafted Host header, potentially achieving arbitrary code execution or persistent denial of service on the extender.

Affected Products

• Netgear WNCE3001 wireless range extender
• Firmware version 1.0.0.50
• HTTP POST request handler (http_d function)

Discovery Timeline

• 2025-06-24 - CVE-2025-6565 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-6565

Vulnerability Analysis

The flaw exists in the embedded HTTP server (http_d) that processes inbound POST requests on the WNCE3001. When the server parses the HTTP Host header, it copies the attacker-controlled value into a fixed-size stack buffer without enforcing length validation. Supplying a header longer than the destination buffer overwrites adjacent stack frames, including the saved return address.

Because the device firmware typically lacks modern exploit mitigations such as stack canaries, address space layout randomization (ASLR), and non-executable stacks, controlling the saved return address can redirect execution to attacker-supplied shellcode or to existing code gadgets. The HTTP daemon usually runs with elevated privileges on consumer router firmware, so successful exploitation grants control over the device.

Root Cause

The root cause is the use of an unbounded string copy when processing the HTTP Host header inside http_d. The function trusts the request-supplied length and writes directly into a fixed stack allocation. This pattern matches CWE-119 and is characteristic of legacy C-based embedded HTTP servers that rely on functions such as strcpy or sprintf without bounds checking.

Attack Vector

The attack is network-based and requires the attacker to reach the device's HTTP management interface. An attacker sends a specially crafted HTTP POST request with an oversized Host header. When the device's HTTP service parses the request, the overflow occurs in http_d. Public proof-of-concept material is available in the GitHub PoC Repository and referenced in VulDB #313737. No verified exploitation code is reproduced here; refer to the linked advisories for technical details.

Detection Methods for CVE-2025-6565

Indicators of Compromise

• HTTP POST requests to the WNCE3001 management interface containing abnormally long Host header values, typically exceeding several hundred bytes.
• Unexpected reboots, watchdog resets, or crashes of the http_d process visible in device system logs.
• Outbound connections originating from the extender to unfamiliar external IP addresses, indicating possible post-exploitation activity.

Detection Strategies

• Inspect HTTP traffic at network choke points for Host headers that exceed RFC-reasonable lengths (for example, greater than 255 bytes).
• Deploy network intrusion detection signatures that flag malformed HTTP requests targeting Netgear extender management endpoints.
• Monitor for repeated POST requests from a single source against extender IP addresses, which can indicate exploitation attempts or fuzzing.

Monitoring Recommendations

• Forward syslog and management-plane events from Netgear devices to a centralized SIEM for correlation with network telemetry.
• Baseline normal administrative traffic to the extender and alert on deviations such as POSTs from non-management subnets.
• Track external scanner activity against TCP/80 and TCP/443 on devices identified as WNCE3001 to identify pre-exploitation reconnaissance.

How to Mitigate CVE-2025-6565

Immediate Actions Required

• Restrict access to the WNCE3001 web management interface to trusted internal hosts using firewall or ACL rules.
• Disable remote management on the extender so the HTTP service is not reachable from the WAN side.
• Inventory all WNCE3001 devices on the network and validate firmware versions against 1.0.0.50 to identify exposure.
• Place affected devices on a segmented VLAN with no ability to initiate outbound connections to the internet.

Patch Information

At the time of NVD publication, no vendor-issued firmware fix had been linked in the CVE record. The WNCE3001 is a legacy product line, and customers should consult the Netgear Official Website for the latest support status and any out-of-band security advisories. If no patch is available, treat the device as end-of-life and plan replacement with a currently supported model.

Workarounds

• Replace the affected WNCE3001 extender with a currently supported model that receives security updates.
• Block inbound TCP/80 and TCP/443 to the device from untrusted networks at the upstream firewall.
• Require VPN access for any administrative interaction with the extender's web interface.
• Disable Universal Plug and Play (UPnP) on upstream routers to prevent automatic exposure of the management port.

# Example: restrict access to the WNCE3001 management interface using iptables
# Allow only the administrative workstation (192.0.2.10) to reach the extender (192.0.2.50)
iptables -A FORWARD -s 192.0.2.10 -d 192.0.2.50 -p tcp --dport 80 -j ACCEPT
iptables -A FORWARD -d 192.0.2.50 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.0.2.50 -p tcp --dport 443 -j DROP