PVS-Studio warning V597 for Crypto++

void CAST256::Base::UncheckedSetKey(const byte *userKey,
  unsigned int keylength, const NameValuePairs &)
{
  AssertValidKeyLength(keylength);
  word32 kappa[8];
  ...
  memset(kappa, 0, sizeof(kappa));
}

This suspicious code was found in Crypto++ project by PVS-Studio static code analyzer.
Warning message is:
V597 The compiler could delete the 'memset' function call, which is used to flush 'kappa' buffer. The RtlSecureZeroMemory() function should be used to erase the private data. cryptlib cast.cpp 293

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