diff -Naur openexr-2.3.0/exrmakepreview/makePreview.cpp openexr-2.3.0-CVE-2020-16588/exrmakepreview/makePreview.cpp
--- openexr-2.3.0/exrmakepreview/makePreview.cpp	2018-08-10 03:35:00.000000000 +0200
+++ openexr-2.3.0-CVE-2020-16588/exrmakepreview/makePreview.cpp	2021-01-09 13:57:41.343549520 +0100
@@ -120,8 +120,8 @@
     previewHeight = max (int (h / (w * a) * previewWidth + .5f), 1);
     previewPixels.resizeErase (previewHeight, previewWidth);
 
-    float fx = (previewWidth  > 0)? (float (w - 1) / (previewWidth  - 1)): 1;
-    float fy = (previewHeight > 0)? (float (h - 1) / (previewHeight - 1)): 1;
+    float fx = (previewWidth  > 1)? (float (w - 1) / (previewWidth  - 1)): 1;
+    float fy = (previewHeight > 1)? (float (h - 1) / (previewHeight - 1)): 1;
     float m  = Math<float>::pow (2.f, IMATH_NAMESPACE::clamp (exposure + 2.47393f, -20.f, 20.f));
 
     for (int y = 0; y < previewHeight; ++y)