The problem is that YAML is used by Rails & Co as a parser for untrusted user-provided data. It does not matter if there is buggy implementation in Python/Perl

The problem is that YAML is used by Rails & Co as a parser for untrusted user-provided data. It does not matter if there is buggy implementation in Python/Perl if nobody use them. If other framework were using YAML in this fashion, yesterday will be the time to look for security holes in those implementations.