https://github.com/rsyslog/rsyslog/issues/3346

--- a/tools/omusrmsg.c
+++ b/tools/omusrmsg.c
@@ -261,7 +261,7 @@ static rsRetVal wallmsg(uchar* pMsg, instanceData *pData)
 
 		/* compute the device name */
 		strcpy(p, _PATH_DEV);
-		memcpy(p, ut.ut_line, UNAMESZ);
+		strncat(p, ut.ut_line, UNAMESZ);
 
 		/* we must be careful when writing to the terminal. A terminal may block
 		 * (for example, a user has pressed <ctl>-s). In that case, we can not