CVE-2026-10188: Tenda W12 Buffer Overflow Vulnerability

CVE-2026-10188 Overview

CVE-2026-10188 is a stack-based buffer overflow vulnerability in the Tenda W12 wireless access point running firmware version 3.0.0.7(4763). The flaw resides in the cgistaKickOff function within the /bin/httpd binary. Attackers can trigger the overflow by manipulating the staMac argument supplied to the affected CGI handler. The vulnerability is reachable over the network and a public exploit has been released, increasing the likelihood of opportunistic abuse against exposed devices. The issue is tracked under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer).

Critical Impact
Remote attackers with low privileges can corrupt stack memory in the embedded httpd process, enabling denial of service and potential remote code execution on affected Tenda W12 access points.

Affected Products

Tenda W12 wireless access point
Firmware version 3.0.0.7(4763)
/bin/httpd web management daemon

Discovery Timeline

2026-05-31 - CVE-2026-10188 published to NVD
2026-06-01 - Last updated in NVD database

Technical Details for CVE-2026-10188

Vulnerability Analysis

The vulnerability exists in the cgistaKickOff handler exported by the embedded httpd web server on the Tenda W12. This CGI endpoint accepts a staMac parameter that represents the MAC address of a station to be disconnected from the access point. The handler copies the attacker-controlled value into a fixed-size stack buffer without validating its length, producing a classic stack-based buffer overflow.

Because the overflowed buffer resides on the call stack, sufficiently long input overwrites the saved return address and adjacent local variables. On MIPS or ARM-based embedded devices typical of the Tenda W12 platform, this corruption can be leveraged to redirect control flow. The exploit archive published as Tenda W12 cgistaKickOff overflow.zip demonstrates how the parameter can be weaponized against the running web service.

Root Cause

The root cause is the absence of bounds checking when the cgistaKickOff function processes the staMac argument. The handler relies on an unsafe copy operation into a stack buffer sized for a valid MAC address string. Any input that exceeds the expected length corrupts adjacent stack memory, including the saved frame pointer and return address.

Attack Vector

The attack is performed remotely against the device's HTTP management interface. An authenticated session with low privileges is required to reach the vulnerable CGI endpoint, after which a crafted request containing an oversized staMac value triggers the overflow. The vulnerability mechanism is described in the VulDB advisory for CVE-2026-10188 and the published Tenda W12 Exploit Archive.

Detection Methods for CVE-2026-10188

Indicators of Compromise

HTTP requests to the device management interface targeting the cgistaKickOff CGI endpoint with abnormally long staMac parameter values.
Unexpected restarts or crashes of the /bin/httpd process on Tenda W12 access points.
Outbound connections from the access point to unknown hosts following management plane requests.

Detection Strategies

Inspect HTTP request logs from network sensors for staMac parameter values that exceed the 17-byte length of a standard MAC address representation.
Alert on repeated POST or GET requests to cgistaKickOff originating from a single client within a short interval.
Correlate device watchdog reboots with preceding requests to the web management interface.

Monitoring Recommendations

Restrict access to the Tenda W12 management interface to a dedicated administrative VLAN and monitor for east-west connections to that subnet.
Capture and retain HTTP request bodies at the network edge to support retroactive hunting against the cgistaKickOff endpoint.
Track device uptime and configuration drift to identify silent compromise of the access point.

How to Mitigate CVE-2026-10188

Immediate Actions Required

Remove the Tenda W12 management interface from any untrusted network and block external access to its HTTP service.
Rotate administrative credentials for the device, since authenticated access is required to reach the vulnerable endpoint.
Audit recent management plane activity for requests targeting cgistaKickOff with oversized parameters.

Patch Information

No vendor patch has been published in the referenced advisories at the time of disclosure. Monitor the Tenda official website and the VulDB entry for CVE-2026-10188 for firmware updates addressing the cgistaKickOff overflow.

Workarounds

Disable remote management on the WAN interface and enforce access from a restricted management subnet only.
Place the access point behind a network firewall that filters HTTP requests carrying oversized staMac parameters.
Consider replacing affected devices with supported hardware if vendor remediation is not available within an acceptable timeframe.

bash

# Example firewall rule to restrict management access to a trusted subnet
iptables -A INPUT -p tcp --dport 80 -s 10.10.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP