diff --git a/hw/vfb/InitOutput.c b/hw/vfb/InitOutput.c
index 94a227b40..a2e728f44 100644
--- a/hw/vfb/InitOutput.c
+++ b/hw/vfb/InitOutput.c
@@ -694,7 +694,7 @@ vfbAllocateFramebufferMemory(vfbScreenInfoPtr pvfb)
 #endif
 
     case NORMAL_MEMORY_FB:
-        pvfb->pXWDHeader = (XWDFileHeader *) malloc(pvfb->sizeInBytes);
+        pvfb->pXWDHeader = (XWDFileHeader *) calloc(1, pvfb->sizeInBytes);
         break;
     }