diff --git a/ANNOUNCE b/ANNOUNCE
index 0bb5e29346cbd927c5a553043d6b807d54aee9b9..37ff2f941a63d74d99b67d28799a29bdcf567159 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -212,6 +212,7 @@ Version 1.6.0beta11 [February 16, 2012]
     Apps are responsible for checking to see if that happened.
 
 Version 1.6.0beta12 [February 17, 2012]
+  Increase num_palette to invalid_index + 1, not to invalid_index.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
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diff --git a/CHANGES b/CHANGES
index 97063ac4ad6a264b0064e216664ea6bf1bc40fc8..8429c2fc6ca7d9fd7ba9e6d516a7f52470b23aea 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3963,6 +3963,7 @@ Version 1.6.0beta11 [February 16, 2012]
     Apps are responsible for checking to see if that happened.
 
 Version 1.6.0beta12 [February 17, 2012]
+  Increase num_palette to invalid_index + 1, not to invalid_index.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/pngread.c b/pngread.c
index 54138bb6f7551e8a5726ddcbfe8c579355651fc8..968a3920c7a6108d6f42b34b9ad29974aabc3f83 100644
--- a/pngread.c
+++ b/pngread.c
@@ -537,7 +537,7 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
             if (*rp >= png_ptr->num_palette)
             {
                png_warning(png_ptr,"Found invalid palette index");
-               png_ptr->num_palette=*rp;
+               png_ptr->num_palette=*rp + 1;
             }
             rp++;
          }