Copied from Fedora.

http://pkgs.fedoraproject.org/cgit/libwmf.git/tree/libwmf-0.2.8.4-CVE-2007-2756.patch

--- libwmf-0.2.8.4/src/extra/gd/gd_png.c	1 Apr 2007 20:41:01 -0000	1.21.2.1
+++ libwmf-0.2.8.4/src/extra/gd/gd_png.c	16 May 2007 19:06:11 -0000
@@ -78,8 +78,11 @@
 gdPngReadData (png_structp png_ptr,
 	       png_bytep data, png_size_t length)
 {
-  gdGetBuf (data, length, (gdIOCtx *)
-	    png_get_io_ptr (png_ptr));
+  int check;
+  check = gdGetBuf (data, length, (gdIOCtx *) png_get_io_ptr (png_ptr));
+  if (check != length) {
+    png_error(png_ptr, "Read Error: truncated data");
+  }
 }
 
 static void
