diff --git a/src/d_net.cpp b/src/d_net.cpp
index cbce9d309..73ad037ce 100644
--- a/src/d_net.cpp
+++ b/src/d_net.cpp
@@ -2057,6 +2057,7 @@ void FDynamicBuffer::SetData (const BYTE *data, int len)
 	{
 		m_Len = 0;
 		M_Free(m_Data);
+		m_Data = NULL;
 	}
 }