Index: src/vdbeaux.c
==================================================================
--- src/vdbeaux.c
+++ src/vdbeaux.c
@@ -3371,11 +3371,12 @@
   u32 notUsed;
   const unsigned char *aKey = (const unsigned char*)pKey;
 
   if( CORRUPT_DB ) return;
   idx = getVarint32(aKey, szHdr);
-  assert( szHdr<=nKey );
+  assert( nKey>=0 );
+  assert( szHdr<=(u32)nKey );
   while( idx<szHdr ){
     idx += getVarint32(aKey+idx, notUsed);
     nField++;
   }
   assert( nField <= pKeyInfo->nField+pKeyInfo->nXField );