Tenda FH1206 v02.03.01.35 was discovered to contain a stack-based buffer overflow vulnerability in the fromPptpUserAdd function. The vulnerability can be triggered via the modino, username, newpwd, or pptpdnetseg parameters, all of which are passed via HTTP POST and used in unsafe sprintf calls without proper length validation. A remote attacker can exploit this flaw through a crafted POST request, which may cause a Denial of Service (DoS). In certain scenarios, this issue could potentially be leveraged to achieve remote code execution.