diff --git a/src/libFLAC/stream_decoder.c b/src/libFLAC/stream_decoder.c
index 04ce7cd..519b0c3 100644
--- a/src/libFLAC/stream_decoder.c
+++ b/src/libFLAC/stream_decoder.c
@@ -2665,6 +2665,11 @@ FLAC__bool read_subframe_lpc_(FLAC__StreamDecoder *decoder, unsigned channel, un
 	/* read qlp shift */
 	if(!FLAC__bitreader_read_raw_int32(decoder->private_->input, &i32, FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN))
 		return false; /* read_callback_ sets the state for us */
+	if(i32 < 0) {
+		send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC);
+		decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
+		return true;
+	}
 	subframe->quantization_level = i32;
 
 	/* read quantized lp coefficiencts */