Index: ext/gd/libgd/gd_png.c
===================================================================
RCS file: /repository/php-src/ext/gd/libgd/gd_png.c,v
retrieving revision 1.17.4.2.2.5.2.3
diff -u -r1.17.4.2.2.5.2.3 gd_png.c
--- ext/gd/libgd/gd_png.c	14 Jan 2009 10:16:15 -0000	1.17.4.2.2.5.2.3
+++ ext/gd/libgd/gd_png.c	10 Mar 2009 11:12:02 -0000
@@ -650,6 +650,12 @@
 		png_set_PLTE(png_ptr, info_ptr, palette, colors);
 	}
 
+	if (colors <= 0 && !im->trueColor) {
+		php_gd_error("gd-png error: Invalid number of colors in palette./martin");
+		png_destroy_write_struct (&png_ptr, &info_ptr);
+		return;
+	}
+
 	/* write out the PNG header info (everything up to first IDAT) */
 	png_write_info(png_ptr, info_ptr);