diff --git a/pngrutil.c b/pngrutil.c
index 8f8edbc..5ca4dcb 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -866,7 +866,7 @@ void /* PRIVATE */
 png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
 {
    png_color palette[PNG_MAX_PALETTE_LENGTH];
-   int num, i;
+   int max_palette_length, num, i;
 #ifdef PNG_POINTER_INDEXING_SUPPORTED
    png_colorp pal_ptr;
 #endif
@@ -927,6 +927,14 @@ png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
    /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
    num = (int)length / 3;
 
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+       max_palette_length = (1 << png_ptr->bit_depth);
+   else
+       max_palette_length = PNG_MAX_PALETTE_LENGTH;
+
+   if (num > max_palette_length)
+       num = max_palette_length;
+
 #ifdef PNG_POINTER_INDEXING_SUPPORTED
    for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
    {
@@ -959,7 +967,7 @@ png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
 #endif
    {
-      png_crc_finish(png_ptr, 0);
+      png_crc_finish(png_ptr, (int) length - num * 3);
    }
 
 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
diff --git a/pngset.c b/pngset.c
index 5f62af1..42e0dc2 100644
--- a/pngset.c
+++ b/pngset.c
@@ -513,12 +513,17 @@ png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
     png_const_colorp palette, int num_palette)
 {
 
+   png_uint_32 max_palette_length;
+
    png_debug1(1, "in %s storage function", "PLTE");
 
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 
-   if (num_palette < 0 || num_palette > PNG_MAX_PALETTE_LENGTH)
+   max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
+      (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
+
+   if (num_palette < 0 || num_palette > (int) max_palette_length)
    {
       if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
          png_error(png_ptr, "Invalid palette length");
diff --git a/pngwrite.c b/pngwrite.c
index 3c8cbbe..39ef69e 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -206,7 +206,7 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
       png_write_PLTE(png_ptr, info_ptr->palette,
           (png_uint_32)info_ptr->num_palette);
 
-   else if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) !=0)
+   else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       png_error(png_ptr, "Valid palette required for paletted images");
 
 #ifdef PNG_WRITE_tRNS_SUPPORTED
diff --git a/pngwutil.c b/pngwutil.c
index 9e6019e..01be584 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -922,17 +922,20 @@ void /* PRIVATE */
 png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
     png_uint_32 num_pal)
 {
-   png_uint_32 i;
+   png_uint_32 max_palette_length, i;
    png_const_colorp pal_ptr;
    png_byte buf[3];
 
    png_debug(1, "in png_write_PLTE");
 
+   max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
+       (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
+
    if ((
 #ifdef PNG_MNG_FEATURES_SUPPORTED
        (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 &&
 #endif
-       num_pal == 0) || num_pal > 256)
+       num_pal == 0) || num_pal > max_palette_length)
    {
       if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       {