diff --git a/OpenEXR/IlmImf/ImfDwaCompressor.cpp b/OpenEXR/IlmImf/ImfDwaCompressor.cpp
index 872c8c7d1e..c378f2e47e 100644
--- a/OpenEXR/IlmImf/ImfDwaCompressor.cpp
+++ b/OpenEXR/IlmImf/ImfDwaCompressor.cpp
@@ -2533,7 +2533,7 @@ DwaCompressor::uncompress
 
     if (acCompressedSize > 0)
     {
-        if (totalAcUncompressedCount*sizeof(unsigned short) > _packedAcBufferSize)
+        if ( !_packedAcBuffer || totalAcUncompressedCount*sizeof(unsigned short) > _packedAcBufferSize)
         {
             throw IEX_NAMESPACE::InputExc("Error uncompressing DWA data"
                                 "(corrupt header).");