Executive brief
A security vulnerability exists in the Tenda F456 router, a device used to provide wireless internet connectivity. An attacker can exploit this flaw by sending a specially crafted web request to the device's management interface. If successful, this could allow the attacker to crash the router, causing a service outage, or potentially take full control of the device to monitor or redirect network traffic.
Technical details
A stack-based buffer overflow vulnerability exists in the 'httpd' component of Tenda F456 firmware version 1.0.0.5. The flaw is located within the 'fromWrlclientSet' function in the '/goform/WrlclientSet' file. The vulnerability is triggered when the function processes the user-provided 'GO' parameter; it fails to perform adequate length checks before passing the data to 'sprintf' within the 'ask_to_reboot' function. An authenticated remote attacker can exploit this by sending a POST request with an oversized 'GO' parameter, leading to a buffer overflow of the 's_1' stack buffer. This can result in a denial of service (DoS) or remote code execution (RCE). Public exploit code (PoC) has been disclosed.
Affected products
- Tenda F456 1.0.0.5
Timeline
- 2026-04-27: disclosed: Vulnerability disclosed and assigned CVE-2026-7101
- 2026-04-27: advisory