Redcarpet and escape_utils use different versions of houdini underneath. Unfortunately, that means any project with both will have problems.

escape_utils_redcarpet.rb

require 'redcarpet' # => 2.2.2
require 'escape_utils' # => 0.3.2

EscapeUtils.escape_html("test")

__END__

ruby(11004,0x7fff75318960) malloc: *** error for object 0x106a20cd0: pointer being realloc'd was not allocated
*** set a breakpoint in malloc_error_break to debug
Abort trap: 6

redcarpet_escape_utils.rb

require 'escape_utils' # => 0.3.2
require 'redcarpet' # => 2.2.2

puts EscapeUtils.escape_html(%Q{"'^test})
markdown = Redcarpet::Markdown.new(Redcarpet::Render::HTML, :autolink => true, :space_after_headers => true)
puts markdown.render <<-END
# Hello
https://www.google.com
END

__END__

&quot;&#39;^test
<h1></h1>

<p>ef="">��specificationhttps://www.google.com</a></p>