diff --git a/cpp/core/src/zxing/common/CharacterSetECI.cpp b/cpp/core/src/zxing/common/CharacterSetECI.cpp
index 80603c6cb..8386208b5 100644
--- a/cpp/core/src/zxing/common/CharacterSetECI.cpp
+++ b/cpp/core/src/zxing/common/CharacterSetECI.cpp
@@ -16,8 +16,8 @@
  */
 
 #include <zxing/common/CharacterSetECI.h>
-#include <sstream>
 #include <zxing/common/IllegalArgumentException.h>
+#include <zxing/FormatException.h>
 
 using std::string;
 
@@ -94,9 +94,7 @@ void CharacterSetECI::addCharacterSet(int const* values, char const* const* name
 
 CharacterSetECI* CharacterSetECI::getCharacterSetECIByValue(int value) {
   if (value < 0 || value >= 900) {
-    std::ostringstream oss;
-    oss << "Bad ECI value: " << value;
-    throw IllegalArgumentException(oss.str().c_str());
+    throw FormatException();
   }
   return VALUE_TO_ECI[value];
 }
diff --git a/cpp/core/src/zxing/qrcode/decoder/DecodedBitStreamParser.cpp b/cpp/core/src/zxing/qrcode/decoder/DecodedBitStreamParser.cpp
index 1a208e61d..83ef51239 100644
--- a/cpp/core/src/zxing/qrcode/decoder/DecodedBitStreamParser.cpp
+++ b/cpp/core/src/zxing/qrcode/decoder/DecodedBitStreamParser.cpp
@@ -275,6 +275,9 @@ void DecodedBitStreamParser::decodeAlphanumericSegment(Ref<BitSource> bits_,
   ostringstream bytes;
   // Read two characters at a time
   while (count > 1) {
+    if (bits.available() < 11) {
+      throw FormatException();
+    }
     int nextTwoCharsBits = bits.readBits(11);
     bytes << toAlphaNumericChar(nextTwoCharsBits / 45);
     bytes << toAlphaNumericChar(nextTwoCharsBits % 45);
@@ -324,7 +327,7 @@ namespace {
       int secondThirdBytes = bits.readBits(16);
       return ((firstByte & 0x1F) << 16) | secondThirdBytes;
     }
-    throw IllegalArgumentException("Bad ECI bits starting with byte " + firstByte);
+    throw FormatException();
   }
 }