  cf2_checkTransform( const CF2_Matrix*  transform,
                      CF2_Int            unitsPerEm )
  {
    CF2_Fixed  maxScale;


    FT_ASSERT( unitsPerEm > 0 );

    if ( transform->a <= 0 || transform->d <= 0 )
      return FT_THROW( Invalid_Size_Handle );

    FT_ASSERT( transform->b == 0 && transform->c == 0 );
    FT_ASSERT( transform->tx == 0 && transform->ty == 0 );

    if ( unitsPerEm > 0x7FFF )
      return FT_THROW( Glyph_Too_Big );

    maxScale = FT_DivFix( CF2_MAX_SIZE, cf2_intToFixed( unitsPerEm ) );

    if ( transform->a > maxScale || transform->d > maxScale )
      return FT_THROW( Glyph_Too_Big );

    return FT_Err_Ok;
  }

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.