CVE-2024-0532: Tenda A15 Buffer Overflow Vulnerability

CVE-2024-0532 Overview

CVE-2024-0532 is a stack-based buffer overflow in the Tenda A15 wireless router running firmware version 15.13.07.13. The flaw resides in the set_repeat5 function of the /goform/WifiExtraSet endpoint within the Web-based Management Interface. Attackers can trigger the overflow by manipulating the wpapsk_crypto2_4g or wpapsk_crypto5g parameters. The vulnerability is remotely reachable over the network and requires only authenticated access to the management interface. Public proof-of-concept documentation has been disclosed, and the vendor did not respond to disclosure attempts. The weakness is tracked under [CWE-119] and [CWE-787], covering improper memory buffer restriction and out-of-bounds write conditions.

Critical Impact
Successful exploitation leads to memory corruption on the device and can enable arbitrary code execution, resulting in full compromise of the router.

Affected Products

Tenda A15 hardware device
Tenda A15 firmware version 15.13.07.13
Deployments exposing the Web-based Management Interface

Discovery Timeline

2024-01-15 - CVE-2024-0532 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD

Technical Details for CVE-2024-0532

Vulnerability Analysis

The vulnerability lives in the set_repeat5 handler bound to the /goform/WifiExtraSet endpoint of the Tenda A15 router web management interface. The handler consumes attacker-controlled request parameters and copies them into fixed-size stack buffers without validating input length. Submitting oversized values for wpapsk_crypto2_4g or wpapsk_crypto5g overwrites adjacent stack memory, including saved return addresses and local control data.

Exploitation requires network reachability to the management interface and elevated privilege on the device, according to the CVSS 4.0 vector. On embedded MIPS-based Tenda devices, buffer overflows in goform handlers commonly permit attacker-controlled overwrite of the return address, enabling redirection of execution flow. Given the absence of modern exploit mitigations on the affected firmware, an attacker who controls the overflow contents can pivot to arbitrary code execution as the process running the HTTP daemon.

Root Cause

The root cause is missing bounds checking on user-supplied POST parameters before they are copied into stack-allocated buffers inside set_repeat5. The function trusts the length of wpapsk_crypto2_4g and wpapsk_crypto5g values without applying a maximum length constraint or safe copy primitive, matching the [CWE-787] out-of-bounds write pattern.

Attack Vector

An authenticated attacker sends a crafted HTTP POST request to /goform/WifiExtraSet with an oversized wpapsk_crypto2_4g or wpapsk_crypto5g payload. When the router's HTTP service dispatches to set_repeat5, the unchecked copy overwrites the stack frame. If the management interface is exposed to a wider network segment, the attack surface grows correspondingly. Technical details are documented in the GitHub PoC write-up and the VulDB entry #250702.

Detection Methods for CVE-2024-0532

Indicators of Compromise

HTTP POST requests to /goform/WifiExtraSet containing abnormally long wpapsk_crypto2_4g or wpapsk_crypto5g parameter values
Unexpected reboots, service crashes, or watchdog resets of the router HTTP daemon following administrative requests
Configuration changes on the router that do not correspond to legitimate administrative activity

Detection Strategies

Deploy network intrusion detection signatures that flag oversized string parameters posted to /goform/WifiExtraSet on Tenda management interfaces
Inspect web application firewall logs for POST bodies exceeding expected WPA passphrase length limits (typically 63 characters)
Correlate router crash events with preceding HTTP administrative traffic to identify exploitation attempts

Monitoring Recommendations

Forward router syslog and HTTP access logs to a centralized platform for longitudinal analysis
Alert on any external source address reaching the router management interface
Track authentication events on the management interface and flag anomalous session activity

How to Mitigate CVE-2024-0532

Immediate Actions Required

Restrict access to the Tenda A15 web management interface to trusted management VLANs only
Disable remote WAN-side administration if enabled on the device
Rotate administrator credentials and enforce strong, unique passwords for the management interface
Isolate the affected router from sensitive network segments until patched firmware is available

Patch Information

The vendor did not respond to disclosure attempts, and no official patched firmware for Tenda A15 version 15.13.07.13 has been published at the time of NVD entry. Monitor the Tenda official website for firmware updates addressing the set_repeat5 handler.

Workarounds

Block inbound access to /goform/WifiExtraSet at an upstream firewall or reverse proxy where feasible
Place the router behind a segmented management network reachable only from designated administrator hosts
Consider replacing the device with a supported model if the vendor does not release a fix

bash

# Example: restrict router management access to a single admin host using iptables upstream
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -s <admin_host_ip> -j ACCEPT
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -s <admin_host_ip> -j ACCEPT
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -j DROP