--- jhead-3.00.orig/exif.c
+++ jhead-3.00/exif.c
@@ -1019,7 +1019,7 @@ void process_EXIF (unsigned char * ExifS
 
     FirstOffset = Get32u(ExifSection+12);
     if (FirstOffset < 8 || FirstOffset > 16){
-        if (FirstOffset < 16 || FirstOffset > length-16){
+        if (FirstOffset < 16 || length < 16 || FirstOffset > length-16){
             ErrNonfatal("invalid offset for first Exif IFD value",0,0);
             return;
         }