Sox segfault when using --norm without [=dB-level]

[James Rudd]

After applying the recent security update sox:amd64 (14.4.1-5ubuntu0.1, 14.4.1-5+deb8u4ubuntu0.1) sox now causes a segmentation fault when run with the --norm option. If I change this to --norm=-3 it does not crash.

e.g
Running this causes a "Segmentation fault (core dumped)"
$ /usr/bin/sox ${SOURCE}*.wav ${DEST}.wav --norm

while running as follows is fine.
$ /usr/bin/sox ${SOURCE}*.wav ${DEST}.wav --norm=-3

In the documentation --norm is an allowed form of normailse.

System details:

Description: Ubuntu 16.04.6 LTS
Release: 16.04

$ apt-cache policy sox
sox:
  Installed: 14.4.1-5+deb8u4ubuntu0.1
  Candidate: 14.4.1-5+deb8u4ubuntu0.1
  Version table:
 *** 14.4.1-5+deb8u4ubuntu0.1 500
        500 http://au.archive.ubuntu.com/ubuntu xenial-updates/universe amd64 Packages
        500 http://security.ubuntu.com/ubuntu xenial-security/universe amd64 Packages
        100 /var/lib/dpkg/status
     14.4.1-5 500
        500 http://au.archive.ubuntu.com/ubuntu xenial/universe amd64 Packages