CVE-2024-2899 Overview
CVE-2024-2899 is a stack-based buffer overflow vulnerability in the Tenda AC7 router running firmware version 15.03.06.44. The flaw resides in the fromSetWirelessRepeat function within the /goform/WifiExtraSet endpoint. Attackers can manipulate the wpapsk_crypto argument to overflow a fixed-size stack buffer. The vulnerability is exploitable remotely and a public proof-of-concept has been disclosed. The vendor was contacted before public disclosure but did not respond, leaving the issue unpatched at time of publication.
Critical Impact
Remote attackers with low-privilege access can trigger memory corruption in the router's HTTP management interface, leading to potential arbitrary code execution and full device compromise.
Affected Products
- Tenda AC7 router (hardware)
- Tenda AC7 firmware version 15.03.06.44
- Devices exposing the /goform/WifiExtraSet web management endpoint
Discovery Timeline
- 2024-03-26 - CVE-2024-2899 published to NVD with VulDB identifier VDB-257942
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-2899
Vulnerability Analysis
The vulnerability is a stack-based buffer overflow [CWE-121] and out-of-bounds write [CWE-787] in the fromSetWirelessRepeat handler of the Tenda AC7 web management daemon. This handler processes HTTP requests submitted to the /goform/WifiExtraSet endpoint, which configures wireless repeater settings. Attacker-supplied data in the wpapsk_crypto parameter is copied into a fixed-size stack buffer without bounds checking. Successful exploitation corrupts saved return addresses and local variables on the stack. This can lead to arbitrary code execution in the context of the router's HTTP server, which typically runs with elevated privileges on embedded Linux firmware.
Root Cause
The root cause is missing length validation on the wpapsk_crypto request parameter before it is written into a stack buffer within fromSetWirelessRepeat. Common unsafe string operations such as strcpy or sprintf in embedded HTTP handlers routinely produce this class of defect when parameter sizes are not checked against destination buffer capacity.
Attack Vector
Exploitation requires network reachability to the router's management interface and low-privilege authenticated access. An attacker crafts an HTTP POST request to /goform/WifiExtraSet containing an oversized wpapsk_crypto value. When the handler processes the request, the oversized value overflows the destination buffer and overwrites adjacent stack memory. Because MIPS-based Tenda firmware often lacks modern exploit mitigations such as ASLR or stack canaries, reliable return-oriented programming (ROP) chains are feasible. A public proof-of-concept exists in the referenced GitHub PoC Repository.
Detection Methods for CVE-2024-2899
Indicators of Compromise
- HTTP POST requests to /goform/WifiExtraSet containing abnormally long wpapsk_crypto parameter values.
- Unexpected reboots, crashes, or restart loops of the Tenda AC7 device's httpd process.
- Outbound connections initiated by the router to unknown IP addresses following configuration changes.
- New or unauthorized firmware modifications, DNS settings, or administrative accounts.
Detection Strategies
- Inspect network traffic to router management interfaces for oversized POST bodies targeting /goform/ endpoints.
- Deploy intrusion detection signatures that alert on requests to WifiExtraSet with parameter lengths exceeding expected WPA-PSK values (typically 8–63 characters).
- Monitor for exposure of router administration interfaces to untrusted network segments or the internet.
Monitoring Recommendations
- Log all authenticated sessions to the router web interface and correlate against known administrator IP addresses.
- Track DNS resolution changes on client devices behind the router that may indicate configuration tampering.
- Alert on repeated failed or malformed requests to Tenda /goform/ endpoints from internal hosts.
How to Mitigate CVE-2024-2899
Immediate Actions Required
- Restrict access to the router's web management interface to trusted internal hosts only and disable remote WAN administration.
- Change default administrator credentials and enforce strong passwords to raise the bar for the required low-privilege authentication.
- Segment the router management VLAN from user and IoT devices to limit lateral reach if the device is compromised.
- Evaluate replacing end-of-support Tenda AC7 units with actively maintained hardware, given the vendor's non-response to disclosure.
Patch Information
No vendor patch is available at time of writing. The VulDB submission notes that the vendor was contacted early but did not respond. Consult the VulDB #257942 entry for updates on any future firmware releases from Tenda.
Workarounds
- Disable the wireless repeater configuration feature if it is not required in the deployment.
- Block external access to TCP ports used by the router's HTTP management daemon at the upstream firewall.
- Place the router behind a network segment that requires VPN access for administrative connectivity.
- Monitor for oversized wpapsk_crypto values in HTTP requests using a network IDS such as Suricata or Snort.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
