Executive brief
Tenda W20E is a wireless router used to provide internet connectivity in homes and small offices. A flaw in the web management interface allows an attacker to send specially crafted network requests that overflow memory buffers, causing the router's management process to crash and potentially enabling remote code execution. This could render the device unavailable and allow an attacker to take control of the router.
Technical details
The vulnerability is a stack-based buffer overflow (CWE-121) in the formDelWebAuthWhiteUser function of the Tenda W20E web interface. The vulnerable component uses unbounded strncpy operations to copy attacker-controlled values from the webAuthWhiteUserIndex parameter into 32-byte stack buffers without proper length validation. An attacker can send a specially crafted HTTP request with an oversized webAuthWhiteUserIndex argument to trigger memory corruption. The attack is remotely exploitable over the network without requiring authentication. Exploitation results in denial of service (crash of the web management process) and potentially arbitrary code execution on the device.
Affected products
- Tenda W20E 15.11.0.61068_1546_841_CN_TDC
Timeline
- 2026-09-14: disclosed