Index: ext/fts5/fts5_index.c
==================================================================
--- ext/fts5/fts5_index.c
+++ ext/fts5/fts5_index.c
@@ -1845,17 +1845,21 @@
         /* Next entry is not on the current page */
         while( iOff==0 ){
           fts5SegIterNextPage(p, pIter);
           pLeaf = pIter->pLeaf;
           if( pLeaf==0 ) break;
-          if( (iOff = fts5GetU16(&pLeaf->p[0])) ){
+          if( (iOff = fts5GetU16(&pLeaf->p[0])) && iOff<pLeaf->n ){
             iOff += sqlite3Fts5GetVarint(&pLeaf->p[iOff], (u64*)&pIter->iRowid);
             pIter->iLeafOffset = iOff;
           }
           else if( (iOff = fts5GetU16(&pLeaf->p[2])) ){
             pIter->iLeafOffset = iOff;
             bNewTerm = 1;
+          }
+          if( iOff>=pLeaf->n ){
+            p->rc = FTS5_CORRUPT;
+            return;
           }
         }
       }
 
       /* Check if the iterator is now at EOF. If so, return early. */
@@ -2023,10 +2027,11 @@
 ){
   int iPg = 1;
   int h;
   int bGe = (flags & FTS5INDEX_QUERY_SCAN);
   int bDlidx = 0;                 /* True if there is a doclist-index */
+  Fts5Data *pLeaf;
 
   assert( bGe==0 || (flags & FTS5INDEX_QUERY_DESC)==0 );
   assert( pTerm && nTerm );
   memset(pIter, 0, sizeof(*pIter));
   pIter->pSeg = pSeg;
@@ -2061,25 +2066,29 @@
   }
 
   pIter->iLeafPgno = iPg - 1;
   fts5SegIterNextPage(p, pIter);
 
-  if( pIter->pLeaf ){
+  if( (pLeaf = pIter->pLeaf) ){
     int res;
-    pIter->iLeafOffset = fts5GetU16(&pIter->pLeaf->p[2]);
-    fts5SegIterLoadTerm(p, pIter, 0);
-    fts5SegIterLoadNPos(p, pIter);
-    do {
-      res = fts5BufferCompareBlob(&pIter->term, pTerm, nTerm);
-      if( res>=0 ) break;
-      fts5SegIterNext(p, pIter, 0);
-    }while( pIter->pLeaf && p->rc==SQLITE_OK );
+    pIter->iLeafOffset = fts5GetU16(&pLeaf->p[2]);
+    if( pIter->iLeafOffset<4 || pIter->iLeafOffset>=pLeaf->n ){
+      p->rc = FTS5_CORRUPT;
+    }else{
+      fts5SegIterLoadTerm(p, pIter, 0);
+      fts5SegIterLoadNPos(p, pIter);
+      do {
+        res = fts5BufferCompareBlob(&pIter->term, pTerm, nTerm);
+        if( res>=0 ) break;
+        fts5SegIterNext(p, pIter, 0);
+      }while( pIter->pLeaf && p->rc==SQLITE_OK );
 
-    if( bGe==0 && res ){
-      /* Set iterator to point to EOF */
-      fts5DataRelease(pIter->pLeaf);
-      pIter->pLeaf = 0;
+      if( bGe==0 && res ){
+        /* Set iterator to point to EOF */
+        fts5DataRelease(pIter->pLeaf);
+        pIter->pLeaf = 0;
+      }
     }
   }
 
   if( p->rc==SQLITE_OK && bGe==0 ){
     pIter->flags |= FTS5_SEGITER_ONETERM;
@@ -2523,11 +2532,11 @@
   const u8 *pTerm, int nTerm,     /* Term to seek to (or NULL/0) */
   int iLevel,                     /* Level to iterate (-1 for all) */
   int nSegment,                   /* Number of segments to merge (iLevel>=0) */
   Fts5MultiSegIter **ppOut        /* New object */
 ){
-  int nSeg;                       /* Number of segment-iters in use */
+  int nSeg = 0;                   /* Number of segment-iters in use */
   int iIter = 0;                  /* */
   int iSeg;                       /* Used to iterate through segments */
   Fts5StructureLevel *pLvl;
   Fts5MultiSegIter *pNew;
 
@@ -4926,12 +4935,16 @@
         iKey = FTS5_SEGMENT_ROWID(iSegid, 0, iPrevLeaf);
         pLeaf = fts5DataRead(p, iKey);
         if( pLeaf ){
           i64 iRowid;
           int iRowidOff = fts5GetU16(&pLeaf->p[0]);
-          fts5GetVarint(&pLeaf->p[iRowidOff], (u64*)&iRowid);
-          if( iRowid!=fts5DlidxIterRowid(pDlidx) ) p->rc = FTS5_CORRUPT;
+          if( iRowidOff>=pLeaf->n ){
+            p->rc = FTS5_CORRUPT;
+          }else{
+            fts5GetVarint(&pLeaf->p[iRowidOff], (u64*)&iRowid);
+            if( iRowid!=fts5DlidxIterRowid(pDlidx) ) p->rc = FTS5_CORRUPT;
+          }
           fts5DataRelease(pLeaf);
         }
       }
 
       for(iPg=iPrevLeaf+1; iPg<=(iter.iLeaf + iter.nEmpty); iPg++){