diff --git a/packages/chm/src/chmfiftimain.pas b/packages/chm/src/chmfiftimain.pas
index 6510e30720..2fee065851 100644
--- a/packages/chm/src/chmfiftimain.pas
+++ b/packages/chm/src/chmfiftimain.pas
@@ -821,7 +821,8 @@ begin
   if CopyLastWordCharCount > 0 then
     Result := Copy(ALastWord, 1, CopyLastWordCharCount);
   SetLength(Result, (WordLength-1) + CopyLastWordCharCount);
-  FStream.Read(Result[1+CopyLastWordCharCount], WordLength-1);
+  if WordLength > 1 then
+    FStream.Read(Result[1+CopyLastWordCharCount], WordLength-1);
 end;
 
 function TChmSearchReader.ReadIndexNodeEntry (ALastWord: String;  out AWord: String; out
diff --git a/packages/chm/src/chmreader.pas b/packages/chm/src/chmreader.pas
index fc59ca1ac3..b65f557caf 100644
--- a/packages/chm/src/chmreader.pas
+++ b/packages/chm/src/chmreader.pas
@@ -277,7 +277,7 @@ procedure TChmReader.ReadCommonData;
      repeat
        Stream.Read(buf, 50);
        Result := Result + buf;
-     until Pos(#0, buf) > -1;
+     until IndexByte(buf, 50, 0) <> -1;
      if FixURL then
        Result := StringReplace(Result, '\', '/', [rfReplaceAll]);
    end;