OpenVPN's Windows interactive service (openvpnserv) miscalculates the size of the converted wide-character MULTI_SZ NRPT (Name Resolution Policy Table) domains list. The previous code assumed the input NRPT domains list consisted of ASCII characters only, so when internationalized domain names (IDNs) were passed as UTF-8 the size of the converted list was calculated incorrectly, leading to extra data being read (buffer overread) and stored in the Windows Registry. This issue only affects OpenVPN on Windows.