CVE-2026-16248: Tenda AC10 Buffer Overflow Vulnerability

CVE-2026-16248 Overview

CVE-2026-16248 is a stack-based buffer overflow vulnerability in the Tenda AC10 wireless router running firmware version 16.03.10.09_multi_TDE01. The flaw resides in the fromAdvSetLanip function within /goform/AdvSetLanip, part of the httpd/netctrl component. Attackers can manipulate the GetValue and SetValue arguments to overflow a stack buffer during processing of LAN IP configuration requests. The vulnerability is remotely reachable across the network and requires only low privileges. Public exploit details have been released, increasing the risk of opportunistic exploitation against exposed devices. The weakness is classified under [CWE-119] (improper restriction of operations within the bounds of a memory buffer).

Critical Impact
Authenticated remote attackers can trigger memory corruption in the router's HTTP daemon, enabling denial of service and potential arbitrary code execution on the device.

Affected Products

Tenda AC10 router, firmware 16.03.10.09_multi_TDE01
httpd/netctrl web management component
/goform/AdvSetLanip endpoint handler (fromAdvSetLanip)

Discovery Timeline

2026-07-20 - CVE-2026-16248 published to NVD
2026-07-20 - Last updated in NVD database

Technical Details for CVE-2026-16248

Vulnerability Analysis

The vulnerability exists in the fromAdvSetLanip handler, which processes HTTP POST requests submitted to /goform/AdvSetLanip on the router's embedded web server. This handler reads user-supplied GetValue and SetValue parameters and copies their contents into fixed-size stack buffers without validating input length. When an attacker submits an oversized value, the copy operation writes past the buffer boundary, corrupting adjacent stack memory including the saved return address.

Because the affected process is the router's httpd, which typically runs with elevated privileges, successful memory corruption can lead to full compromise of the device. The estimated exploit probability from EPSS is modest, but a public proof-of-concept has been referenced in the GitHub Tenda AC10 Advisory.

Root Cause

The root cause is missing bounds checking in the fromAdvSetLanip function. User-controlled GetValue and SetValue parameters are copied into stack-allocated buffers using unsafe string operations, mapping to [CWE-119]. No length validation constrains the input before the copy, allowing the stack frame to be overwritten.

Attack Vector

Exploitation requires network access to the router's management interface and a low-privilege authenticated session. An attacker sends a crafted HTTP request to /goform/AdvSetLanip with an oversized GetValue or SetValue argument. The malformed request triggers the overflow inside httpd/netctrl, corrupting execution state.

No verified proof-of-concept code is reproduced here. Technical details are available in the GitHub Tenda AC10 Advisory and VulDB CVE-2026-16248.

Detection Methods for CVE-2026-16248

Indicators of Compromise

HTTP POST requests targeting /goform/AdvSetLanip with abnormally long GetValue or SetValue parameters
Repeated crashes or unexpected reboots of the router httpd process
Configuration changes to LAN IP settings that were not initiated by an administrator

Detection Strategies

Inspect router HTTP request logs for oversized parameter values submitted to /goform/AdvSetLanip
Correlate authentication events with abnormal management-plane traffic patterns
Monitor for outbound connections from the router to unfamiliar hosts, which may indicate post-exploitation activity

Monitoring Recommendations

Enable syslog forwarding from the router to a centralized logging platform for retention and analysis
Alert on repeated httpd restarts or watchdog resets on affected devices
Restrict and monitor administrative access to the router's web management interface

How to Mitigate CVE-2026-16248

Immediate Actions Required

Disable remote (WAN-side) access to the router management interface immediately
Restrict LAN-side access to the web console to trusted administrative hosts only
Rotate router administrator credentials and audit accounts for unauthorized additions
Consult the Tenda Official Website for firmware updates addressing this issue

Patch Information

At the time of publication, no vendor-supplied patch is referenced in the NVD entry for firmware 16.03.10.09_multi_TDE01. Administrators should monitor the Tenda Official Website for updated firmware releases and apply them promptly once available. Additional tracking is available via VulDB Vulnerability #380539.

Workarounds

Place affected routers behind a network segment that blocks untrusted access to TCP management ports
Require VPN access before allowing administrative connections to the router
Replace end-of-support or unpatched devices with hardware that receives active vendor security maintenance

bash

# Example: block external access to the router web interface using upstream firewall rules
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -m state --state NEW -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -m state --state NEW -j DROP