In Godot through 3.1, remote code execution is possible due to the deserialization policy not being applied correctly.

Godot Engine version All versions prior to 2.1.5, all 3.0 versions prior to 3.0.6. contains a Signed/unsigned comparison, wrong buffer size chackes, integer overflow, missing padding initialization vulnerability in (De)Serialization functions (core/io/marshalls.cpp) that can result in DoS (packet of death), possible leak of uninitialized memory. This attack appear to be exploitable via A malformed packet is received over the network by a Godot application that uses built-in serialization (e.g. game server, or game client). Could be triggered by multiplayer opponent. This vulnerability appears to have been fixed in 2.1.5, 3.0.6, master branch after commit feaf03421dda0213382b51aff07bd5a96b29487b.