When using "mput" in smbclient from samba-3.0.23c on a directory with files with multibyte characters in name under UTF-8 locale I've experienced that smbclient sometimes crashes.

Valgring is detecting it is a memory corruption issue - it can be reproduced this way:

$echo $LANG
en_US.UTF-8
$ mkdir /tmp/test
$ cd /tmp/test
$ touch '®' # registered sign
$ valgrind smbclient '//server/share' 'password' \
  -U 'username' -W 'workgroup' -c 'prompt; mput ®'

This detects the following error:
==13333== Invalid write of size 1
==13333==    at 0xB10F9: pull_ucs2 (charcnv.c:1201)
==13333==    by 0xBF9B4: string_replace (util_str.c:392)
==13333==    by 0x23C5C: cmd_mput (client.c:1525)
==13333==    by 0x27C21: process_command_string (client.c:2934)
==13333==    by 0x28A9E: process (client.c:3253)
==13333==    by 0x29B8B: main (client.c:3622)
==13333==  Address 0x4C8CB1C is 0 bytes after a block of size 4 alloc'd
==13333==    at 0x48051F9: malloc (vg_replace_malloc.c:149)
==13333==    by 0x4BF6563E: vasprintf (in /lib/libc-2.4.so)
==13333==    by 0x4BF4D19D: asprintf (in /lib/libc-2.4.so)
==13333==    by 0x23C3A: cmd_mput (client.c:1522)
==13333==    by 0x27C21: process_command_string (client.c:2934)
==13333==    by 0x28A9E: process (client.c:3253)
==13333==    by 0x29B8B: main (client.c:3622)

I have compiled vanilla samba-3.0.23c with debugging symbols and no optimizations using "cd source; ./configure; make CFLAGS='-O0 -g'" to eliminate distribution introduced bugs and to get meaningful output from valgring.