diff --git a/cpp/core/src/zxing/qrcode/decoder/DecodedBitStreamParser.cpp b/cpp/core/src/zxing/qrcode/decoder/DecodedBitStreamParser.cpp
index d209d939c..b3571ed7b 100644
--- a/cpp/core/src/zxing/qrcode/decoder/DecodedBitStreamParser.cpp
+++ b/cpp/core/src/zxing/qrcode/decoder/DecodedBitStreamParser.cpp
@@ -364,6 +364,9 @@ DecodedBitStreamParser::decode(ArrayRef<unsigned char> bytes,
         // We do little with FNC1 except alter the parsed result a bit according to the spec
         fc1InEffect = true;
       } else if (mode == &Mode::STRUCTURED_APPEND) {
+        if (bits.available() < 16) {
+          throw new FormatException();
+        }
         // not really supported; all we do is ignore it
         // Read next 8 bits (symbol sequence #) and 8 bits (parity data), then continue
         bits.readBits(16);