openssl sha1 message digest not matching with NIST vector input?
You read the testvector incorrectly.

I assume you are referring to the following part of the file SHA1ShortMsg.rsp of the FIPS 180-4 vectors: 

[L = 20]

Len = 0 
Msg = 00 
MD = da39a3ee5e6b4b0d3255bfef95601890afd80709


This test vector has length 0, so the specified hash is for an empty message and not for a single zero byte. This openssl command shows the correct result.


  $ echo -n ""|openssl dgst -sha1
  (stdin)= da39a3ee5e6b4b0d3255bfef95601890afd80709