diff --git a/ddprof-lib/src/main/cpp/flightRecorder.cpp b/ddprof-lib/src/main/cpp/flightRecorder.cpp
index 95f710d98..4d5946f23 100644
--- a/ddprof-lib/src/main/cpp/flightRecorder.cpp
+++ b/ddprof-lib/src/main/cpp/flightRecorder.cpp
@@ -870,6 +870,7 @@ void Recording::writeSystemProperties(Buffer* buf) {
             buf->putVar32(start, buf->offset() - start);
             jvmti->Deallocate((unsigned char*)value);
         }
+        jvmti->Deallocate((unsigned char*)key);
     }
     flushIfNeeded(buf);