diff --git a/ANNOUNCE b/ANNOUNCE
index ca529ad..7ff9c6a 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -29,6 +29,7 @@
     failures. Placed the remainder in contrib/pngsuite/interlaced/i*.png.
   Added calls to png_set_*() transforms commonly used by browsers to
     the fuzzer.
+  Initialize trans_color.red, green, and blue == trans_color.gray
 
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diff --git a/CHANGES b/CHANGES
index e34f2d9..274e41a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -6045,6 +6045,7 @@
     failures. Placed the remainder in contrib/pngsuite/interlaced/i*.png.
   Added calls to png_set_*() transforms commonly used by browsers to
     the fuzzer.
+  Initialize trans_color.red, green, and blue == trans_color.gray
 
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diff --git a/pngrutil.c b/pngrutil.c
index 8692933..8081feb 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -1852,6 +1852,9 @@
       png_crc_read(png_ptr, buf, 2);
       png_ptr->num_trans = 1;
       png_ptr->trans_color.gray = png_get_uint_16(buf);
+      png_ptr->trans_color.red = png_ptr->trans_color.gray;
+      png_ptr->trans_color.green = png_ptr->trans_color.gray;
+      png_ptr->trans_color.blue = png_ptr->trans_color.gray;
    }
 
    else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)