CVE-2024-33217: Tenda FH1206 Buffer Overflow Vulnerability

CVE-2024-33217 Overview

CVE-2024-33217 is a stack-based buffer overflow vulnerability in the Tenda FH1206 router running firmware version V1.2.0.8(8155)_EN. The flaw resides in the ip/goform/addressNat endpoint, where the page parameter is processed without proper bounds checking. A remote, unauthenticated attacker can submit a crafted HTTP request to overflow the stack buffer and crash the device. The weakness is categorized as [CWE-121] Stack-based Buffer Overflow.

Critical Impact

Unauthenticated network attackers can trigger a stack overflow in the router's web management interface, resulting in denial of service and the potential for arbitrary code execution on the affected device.

Affected Products

• Tenda FH1206 router (hardware)
• Tenda FH1206 firmware version V1.2.0.8(8155)_EN
• Web management interface endpoint ip/goform/addressNat

Discovery Timeline

• 2024-04-23 - CVE-2024-33217 published to NVD
• 2025-03-17 - Last updated in NVD database

Technical Details for CVE-2024-33217

Vulnerability Analysis

The Tenda FH1206 router exposes a web administration interface that handles NAT configuration requests through the ip/goform/addressNat handler. The handler reads the page HTTP parameter and copies it into a fixed-size stack buffer without validating the input length. When an attacker supplies a page value larger than the destination buffer, the copy operation overwrites adjacent stack memory, including the saved return address.

Because the affected binary is a MIPS-based embedded service running with elevated privileges and typically lacks modern exploit mitigations such as stack canaries and address space layout randomization, the overflow can be leveraged to redirect execution flow. The result ranges from immediate router reboot to arbitrary code execution in the context of the web service.

The vulnerability is reachable over the network and requires no authentication or user interaction. Additional technical context is available in the Notion Document on NAT Configuration.

Root Cause

The root cause is missing input length validation on the page parameter inside the fromAddressNat function. The handler uses an unsafe string copy into a stack-allocated buffer, satisfying the conditions for [CWE-121].

Attack Vector

An attacker sends a single HTTP request to ip/goform/addressNat with an oversized page query parameter. Exploitation requires network reachability to the router's management interface, which is frequently exposed on the LAN and, in misconfigured deployments, on the WAN. No credentials are required.

No public proof-of-concept exploit code is available for this issue. Refer to the linked technical reference for parameter and request structure details.

Detection Methods for CVE-2024-33217

Indicators of Compromise

• HTTP POST or GET requests to /goform/addressNat containing abnormally long page parameter values.
• Unscheduled reboots or watchdog-triggered restarts of the Tenda FH1206 router.
• Web administration interface becoming intermittently unresponsive after specific HTTP requests.

Detection Strategies

• Inspect HTTP traffic destined for the router management interface for page parameter lengths that exceed expected bounds (typically a few dozen bytes).
• Deploy IDS/IPS signatures that flag oversized query parameters targeting Tenda goform endpoints.
• Correlate router crash events with preceding inbound HTTP requests using network flow logs.

Monitoring Recommendations

• Forward router syslog and web access logs to a centralized log platform for review.
• Alert on repeated HTTP requests to /goform/addressNat from a single source within a short time window.
• Monitor for management interface exposure on WAN-facing interfaces using external attack surface scanning.

How to Mitigate CVE-2024-33217

Immediate Actions Required

• Restrict access to the router web management interface to trusted management VLANs or hosts only.
• Disable remote (WAN-side) administration on the Tenda FH1206 if not strictly required.
• Change default administrative credentials and enforce strong passwords on the management interface.
• Place vulnerable devices behind an upstream firewall that filters traffic to /goform/ paths.

Patch Information

At the time of publication, no vendor patch or firmware update is referenced in the NVD entry for CVE-2024-33217. Organizations operating affected devices should monitor the Tenda support portal for firmware updates and consider replacing end-of-life hardware if no fix is released.

Workarounds

• Segment vulnerable routers onto an isolated management network with strict ACLs.
• Block inbound HTTP and HTTPS to the router management interface from untrusted networks.
• Where feasible, replace the FH1206 with a supported device that receives current security updates.

# Example ACL on an upstream firewall to block external access to the router's web UI
# Replace 192.0.2.10 with the router's management IP and 203.0.113.0/24 with trusted admins
iptables -A FORWARD -p tcp -d 192.0.2.10 --dport 80 -s 203.0.113.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d 192.0.2.10 --dport 80 -j DROP
iptables -A FORWARD -p tcp -d 192.0.2.10 --dport 443 -s 203.0.113.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d 192.0.2.10 --dport 443 -j DROP