CVE-2026-36818

Vulnerability

A buffer overflow vulnerability exists in the formAddWewifiWhiteUser function within Shenzhen Tenda Technology Co., Ltd Tenda W20E version v15.11.0.6. The vulnerability is triggered when processing the wewifiWhiteUserInfo parameter, which is retrieved using websGetVar. The strncpy function is used with a length derived from the position of a newline character within the input, which can lead to an overflow if the parameter is sufficiently long [1].

Exploitation

An attacker can exploit this vulnerability by sending a crafted HTTP request to the formAddWewifiWhiteUser CGI endpoint. The request must include a long wewifiWhiteUserInfo parameter, for example, a string of 888 'a' characters followed by 50 or more newline characters, to trigger the buffer overflow [1].

Impact

Successful exploitation of this vulnerability can lead to a Denial of Service (DoS) condition. This may manifest as a process crash or device instability, rendering the affected device unusable [1].

Mitigation

Shenzhen Tenda Technology Co., Ltd Tenda W20E version v15.11.0.6 is affected. The latest version mentioned is V16.01.0.6. No specific patch information or mitigation steps beyond upgrading to a non-vulnerable version have been disclosed in the available references [1].