From 39e82e9ee6d6dd1a227d416411c0197c489e18a6 Mon Sep 17 00:00:00 2001
From: Cristy <urban-warrior@imagemagick.org>
Date: Mon, 18 Sep 2017 15:30:11 -0400
Subject: [PATCH] Unbounded unique colors is problematic

---
 coders/histogram.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/coders/histogram.c b/coders/histogram.c
index 21c76d7c2..2ff1775df 100644
--- a/coders/histogram.c
+++ b/coders/histogram.c
@@ -331,7 +331,8 @@ static MagickBooleanType WriteHISTOGRAMImage(const ImageInfo *image_info,
   }
   histogram=(PixelInfo *) RelinquishMagickMemory(histogram);
   option=GetImageOption(image_info,"histogram:unique-colors");
-  if ((option == (const char *) NULL) || (IsStringTrue(option) != MagickFalse))
+  if ((IsHistogramImage(image,exception) != MagickFalse) || 
+      (IsStringTrue(option) != MagickFalse))
     {
       FILE
         *file;
-- 
2.40.0