diff --git a/libwvdrmengine/cdm/core/src/crypto_session.cpp b/libwvdrmengine/cdm/core/src/crypto_session.cpp
index f531763e..19a55f0b 100644
--- a/libwvdrmengine/cdm/core/src/crypto_session.cpp
+++ b/libwvdrmengine/cdm/core/src/crypto_session.cpp
@@ -155,6 +155,9 @@ bool CryptoSession::GetDeviceUniqueId(std::string* device_id) {
     return false;
   }
 
+  id.resize(id_length + 1);
+  id[id_length] = '\0';
+
   *device_id = reinterpret_cast<const char*>(&id[0]);
   return true;
 }