Hello all, I am the researcher who reported this vulnerability and I don't think it is being added on purpose, here's why:
- It can only be triggered from LAN-side, WAN-side attacker can not directly gain access to intranet without a open redirection via social engineering users inside intranet.
- The hidden backdoor is a code port of older models, which is previously reported (by another security researcher) but not patched properly due to EOL (end of lifecycle)
I have confirmed the patch after it had been released, the backdoor along with another path traversal vulnerability is removed, so panic not, it's a piece of legacy debug code existing there somehow.