batch file eats cpu and RAM using only echo ^?

tldr: ran a batch file with only 1 line in it: echo ^ . This file eats 70-100% of one core and approx. 1k RAM a second...???

While answering this question, I came across some odd behavior in Windows batch files.

I was having some batch file fun to show the OP that you could have a ^ at the end of a line in a batch file for line continuation, example:

file test.bat:

echo How are ^
you today ^
my good fellow

Would output: How are you today my good fellow

I was curious if the command prompt would display a More? from the batch file similar to the command prompt if you just had a line like so in a batch file: echo Do you want some ^

If you did that on the command line it would display More? (as for more input):

C:\>echo Do you want some ^
More?

However, I tried this line (having ONLY this line) in a batch file and some unexplainable behavior happened, so I played around with the script to find that the only time this happens is when an echo statement is the last line and the ^ is the last character of the batch file.

A quick file to reproduce:

file test.bat:

echo ^

Running that batch file on my 64-bit Windows 7 machine ate up 70-100% of one of my cores and would eat roughly 1k of memory every second!!

Running this file also ignored all input (except CTRL+ key presses to end it), though after the file ended the input was still flushed to the console:

C:\>test.bat
(nothing is happening here except CPU/RAM eating)
(I would proceed to type something like "HELLO")
CTRL+C (script ends)
C:\>HELLO
'HELLO' is not recognized an internal .....

My 'search-foo' (Stack Oveflow, Stack Exchange, MSDN, Google and Bing) turned up no results that could explain this odd behavior in a batch file (only what the ^ does on command line and batch files); I would think that if the only line in a batch file was echo ^ it would just end the script and not run until I CTRL+C out of it?

Has any one else noticed this behavior or could explain what might cause this? As well could that lead to any possible avenues of attack on a system?

It's not a major issue (I don't have any batch files that end in echo ^) but it struck me as very peculiar that 1 line of batch results in 1k/s??

(Side note: I'm going to try this same situation out through some programming languages [.NET, Java and C/C++] and some web scripts (JS maybe?) to see what happens as a result)

As it turns out, this is actually a bug in how the command line (more specifically cmd.exe) parses batch files and could lead to a quick denial of service type attack; putting the following line in a batch file (with no new lines) will consume massive amounts of memory very quickly due to this bug (as an example):

^ nul<^

Long story short, when a caret is at the end of the file, the actual end of file is 'ignored' and the file handle 'reset' to 0 (essentially) so that the batch is parsed again (ad infinitum).