diff --git a/Source/ocdm/open_cdm_ext.cpp b/Source/ocdm/open_cdm_ext.cpp
index 703ced13..516408f6 100644
--- a/Source/ocdm/open_cdm_ext.cpp
+++ b/Source/ocdm/open_cdm_ext.cpp
@@ -362,7 +362,7 @@ opencdm_construct_session(struct OpenCDMSystem* system,
     TRACE_L1("Creating a Session for %s", system->keySystem().c_str());
 
     if (system != nullptr) {
-        *session = new OpenCDMSession(system, std::string(initDataType),
+        *session = new OpenCDMSession(system, initDataType ? std::string(initDataType) : std::string(),
                             initData, initDataLength, CDMData,
                             CDMDataLength, licenseType, callbacks, userData);
         result = (*session != nullptr ? OpenCDMError::ERROR_NONE