CVE-2026-114268: Tenda BE3L Pro Buffer Overflow Vulnerability

CVE-2026-114268 Overview

CVE-2026-114268 is a buffer overflow vulnerability affecting Tenda BE3L Pro routers running firmware version 16.03.60.62. The flaw resides in the formWifiBasicSet function handling requests to the /goform/WifiBasicSet endpoint. Attackers can exploit the issue by manipulating the security_5g parameter to trigger memory corruption. The vulnerability is remotely exploitable, and a public proof-of-concept has been released, increasing the probability of opportunistic attacks against exposed devices.

Critical Impact
Remote attackers can trigger memory corruption on affected Tenda BE3L Pro routers through a crafted security_5g parameter, potentially leading to arbitrary code execution or denial of service.

Affected Products

Tenda BE3L Pro router
Firmware version 16.03.60.62
/goform/WifiBasicSet web management endpoint

Discovery Timeline

2026-10-21 - CVE-2026-114268 published to NVD
2026-10-22 - Last updated in NVD database

Technical Details for CVE-2026-114268

Vulnerability Analysis

The vulnerability is a classic stack-based buffer overflow categorized under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer). It resides in the formWifiBasicSet function, which processes HTTP POST requests sent to the /goform/WifiBasicSet endpoint on the router's web management interface. The function reads the security_5g parameter from client-supplied input without enforcing a safe length boundary. Supplying an oversized value overwrites adjacent memory, including saved return addresses on the stack.

Successful exploitation can lead to arbitrary code execution on the device with the privileges of the HTTP daemon, which typically runs as root on consumer routers. At minimum, the condition causes the daemon to crash, resulting in loss of network connectivity for all connected clients. A public exploit has been published to a GitHub repository, lowering the barrier to weaponization.

Root Cause

The root cause is the absence of length validation on the security_5g HTTP parameter before it is copied into a fixed-size stack buffer. The formWifiBasicSet handler trusts attacker-controlled input and uses unsafe string-copy semantics, which is a recurring pattern in Tenda goform handlers.

Attack Vector

An authenticated attacker on the local network, or any attacker who can reach the router's management interface, sends a crafted HTTP POST request to /goform/WifiBasicSet containing an oversized security_5g value. Because management interfaces are sometimes exposed to the WAN or to guest networks, remote exploitation is realistic. The attack requires low privileges and no user interaction.

The vulnerability mechanism follows the standard Tenda goform overflow pattern. Technical details and reproduction steps are available in the GitHub PoC Repository and VulDB CVE-2026-114268 entries.

Detection Methods for CVE-2026-114268

Indicators of Compromise

HTTP POST requests to /goform/WifiBasicSet containing abnormally long security_5g parameter values.
Unexpected reboots, crashes, or httpd process restarts on Tenda BE3L Pro devices.
Outbound connections from the router to unknown hosts following malformed management requests.

Detection Strategies

Inspect network traffic for requests to /goform/WifiBasicSet where parameter length exceeds expected bounds (typically a few dozen bytes).
Deploy IDS signatures matching oversized form parameters targeting Tenda goform endpoints.
Correlate router syslog entries with network capture to identify crash patterns tied to management-interface requests.

Monitoring Recommendations

Restrict and log all access to the router management interface, alerting on unauthorized source IPs.
Monitor for scanning activity against TCP ports hosting the Tenda web interface.
Track public threat intelligence feeds and the VulDB Vulnerability #424700 entry for exploitation reports.

How to Mitigate CVE-2026-114268

Immediate Actions Required

Disable remote WAN-side administration on the Tenda BE3L Pro and restrict management to trusted LAN segments.
Place vulnerable devices behind a firewall that blocks inbound access to the HTTP management interface.
Change default and administrative credentials to limit low-privilege exploitation paths.

Patch Information

At the time of publication, no vendor patch has been identified for firmware 16.03.60.62. Administrators should monitor the Tenda Official Website for firmware updates addressing CVE-2026-114268 and apply them as soon as they become available.

Workarounds

Segment the router onto a management VLAN unreachable from untrusted clients and guest Wi-Fi.
Disable the web management interface when not actively in use, or bind it to a non-default port behind an ACL.
Replace end-of-support or unpatched devices with vendor-supported hardware if a fix is not released in a reasonable timeframe.

bash

# Example firewall rule to restrict router management access
# Allow management only from a dedicated admin host
iptables -A INPUT -p tcp --dport 80 -s 192.0.2.10 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -s 192.0.2.10 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP