diff --git a/src/drivers/gnss/septentrio/sbf/decoder.h b/src/drivers/gnss/septentrio/sbf/decoder.h
index 78a62ebc0f..4c5b73c943 100644
--- a/src/drivers/gnss/septentrio/sbf/decoder.h
+++ b/src/drivers/gnss/septentrio/sbf/decoder.h
@@ -224,7 +224,7 @@ private:
 	bool can_parse() const;
 
 	State _state{State::SearchingSync1};
-	uint16_t _current_index;
+	uint16_t _current_index{0};
 	message_t _message;
 };