diff -r 851de24ecb61 -r 4c10b7956435 src/VersionDictionary.cpp
--- a/src/VersionDictionary.cpp	Sun Sep 20 21:25:47 2009 -0700
+++ b/src/VersionDictionary.cpp	Thu Sep 24 21:46:17 2009 -0700
@@ -134,19 +134,24 @@
         VersionDictionary::Trailer trailer;
         _file->read(trailer);
         _trailerPosition = trailerPos;
+        _previousTrailerPosition = trailer.previousTrailerPosition;
         _count = trailer.count;
         _indexPositions = trailer.indexPositions;
         
         if (trailer.magicNumber1 != VersionDictionary::Trailer::kMagicNumber1
             || trailer.magicNumber2 != VersionDictionary::Trailer::kMagicNumber2)
-            throw File::Error(ERANGE, "No trailer found in file (invalid magic numbers)");\
-
+            throw File::Error("No trailer found in file (invalid magic numbers)");
+        if (_previousTrailerPosition >= _trailerPosition)
+            throw File::Error("Bad VersionDictionary trailer (illegal previousTrailerPosition)");
         
         // Map in the file:
         _file->mapRegion(0, _trailerPosition+sizeof(trailer));
 
         // Verify Indexes:
         for (int i=0; i<256; i++) {
+            if (_indexPositions[i] > 0)
+                if (_indexPositions[i] < _previousTrailerPosition || _indexPositions[i] >= _trailerPosition)
+                    throw File::Error("Bad VersionDictionary trailer (illegal index position)");
             const Index *index = _index(i);
             if (index)
                 index->validate();