diff --git a/libavcodec/exr.c b/libavcodec/exr.c
index 2e008c8f6f..fe5ad69293 100644
--- a/libavcodec/exr.c
+++ b/libavcodec/exr.c
@@ -1825,13 +1825,14 @@ static int decode_frame(AVCodecContext *avctx, void *data,
     avctx->execute2(avctx, decode_block, s->thread_data, NULL, nb_blocks);
 
     // Zero out the end if ymax+1 is not h
-    for (i = 0; i < planes; i++) {
-        ptr = picture->data[i] + ((s->ymax+1) * picture->linesize[i]);
-        for (y = s->ymax + 1; y < avctx->height; y++) {
-            memset(ptr, 0, out_line_size);
-            ptr += picture->linesize[i];
+    if ((s->ymax+1) < avctx->height)
+        for (i = 0; i < planes; i++) {
+            ptr = picture->data[i] + ((s->ymax+1) * picture->linesize[i]);
+            for (y = s->ymax + 1; y < avctx->height; y++) {
+                memset(ptr, 0, out_line_size);
+                ptr += picture->linesize[i];
+            }
         }
-    }
 
     picture->pict_type = AV_PICTURE_TYPE_I;
     *got_frame = 1;