PVS-Studio warning V541 for Firefox

bool AdjustWebSocketHost(relayBuffer& buffer,
                         connection_info_t *ci)
{
  ...
  sprintf(newhost, "%s:%d", newhost,
          PR_ntohs(inet_addr.inet.port));
  ...
}

The code might work, but this is a dangerous game.

This suspicious code was found in Firefox project by PVS-Studio static code analyzer.
Warning message is:
V541 It is dangerous to print the string 'newhost' into itself. ssltunnel.cpp 531

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/