diff --git a/quiche/quic/core/quic_connection.h b/quiche/quic/core/quic_connection.h
index 9fb1aaa..7f58c5e 100644
--- a/quiche/quic/core/quic_connection.h
+++ b/quiche/quic/core/quic_connection.h
@@ -1498,7 +1498,7 @@
     EncryptionLevel decrypted_level = ENCRYPTION_INITIAL;
     QuicPacketHeader header;
     absl::InlinedVector<QuicFrameType, 1> frames;
-    QuicEcnCodepoint ecn_codepoint;
+    QuicEcnCodepoint ecn_codepoint = ECN_NOT_ECT;
   };
 
   QUIC_EXPORT_PRIVATE friend std::ostream& operator<<(
diff --git a/quiche/quic/core/quic_connection_test.cc b/quiche/quic/core/quic_connection_test.cc
index 98027d4..8fb5f78 100644
--- a/quiche/quic/core/quic_connection_test.cc
+++ b/quiche/quic/core/quic_connection_test.cc
@@ -16708,6 +16708,10 @@
             connection_.SupportsMultiplePacketNumberSpaces() ? 1 : 2);
 }
 
+TEST_P(QuicConnectionTest, ReceivedPacketInfoDefaults) {
+  EXPECT_TRUE(QuicConnectionPeer::TestLastReceivedPacketInfoDefaults());
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace quic
diff --git a/quiche/quic/test_tools/quic_connection_peer.cc b/quiche/quic/test_tools/quic_connection_peer.cc
index ad58d9c..3d63682 100644
--- a/quiche/quic/test_tools/quic_connection_peer.cc
+++ b/quiche/quic/test_tools/quic_connection_peer.cc
@@ -582,5 +582,22 @@
   return &connection->peer_ack_ecn_counts_[packet_number_space];
 }
 
+// static
+bool QuicConnectionPeer::TestLastReceivedPacketInfoDefaults() {
+  QuicConnection::ReceivedPacketInfo info{QuicTime::Zero()};
+  return info.destination_address == QuicSocketAddress() &&
+         info.source_address == QuicSocketAddress() &&
+         info.receipt_time == QuicTime::Zero() &&
+         !info.received_bytes_counted && info.length == 0 &&
+         info.destination_connection_id == QuicConnectionId() &&
+         !info.decrypted && info.decrypted_level == ENCRYPTION_INITIAL &&
+         // There's no simple way to compare all the values of QuicPacketHeader.
+         info.frames.empty() && info.ecn_codepoint == ECN_NOT_ECT &&
+         // If the condition below fails, the contents of ReceivedPacketInfo
+         // have changed. Please add the relevant conditions and update the
+         // length below.
+         sizeof(QuicConnection::ReceivedPacketInfo) == 256;
+}
+
 }  // namespace test
 }  // namespace quic
diff --git a/quiche/quic/test_tools/quic_connection_peer.h b/quiche/quic/test_tools/quic_connection_peer.h
index fbdedb3..330be03 100644
--- a/quiche/quic/test_tools/quic_connection_peer.h
+++ b/quiche/quic/test_tools/quic_connection_peer.h
@@ -239,6 +239,8 @@
 
   static QuicEcnCounts* GetEcnCounts(QuicConnection* connection,
                                      PacketNumberSpace packet_number_space);
+
+  static bool TestLastReceivedPacketInfoDefaults();
 };
 
 }  // namespace test