Index: djvulibre-3.5.28/tools/ddjvu.cpp
===================================================================
--- djvulibre-3.5.28.orig/tools/ddjvu.cpp	2020-11-20 17:57:32.000000000 +0100
+++ djvulibre-3.5.28/tools/ddjvu.cpp	2021-05-11 15:14:54.038421444 +0200
@@ -70,6 +70,7 @@
 #include <locale.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <stdint.h>
 
 #ifdef UNIX
 # include <sys/time.h>
@@ -394,7 +395,9 @@ render(ddjvu_page_t *page, int pageno)
     rowsize = rrect.w;
   else
     rowsize = rrect.w * 3; 
-  if (! (image = (char*)malloc(rowsize * rrect.h)))
+  if ((size_t) rowsize > SIZE_MAX / rrect.h)
+    die(i18n("Integer overflow when allocating image buffer for page %d"), pageno);
+  if (! (image = (char*)malloc((size_t) rowsize * rrect.h)))
     die(i18n("Cannot allocate image buffer for page %d"), pageno);
 
   /* Render */