diff --git a/quic/masque/masque_server_backend.cc b/quic/masque/masque_server_backend.cc
index 230f7e7..5b10d6f 100644
--- a/quic/masque/masque_server_backend.cc
+++ b/quic/masque/masque_server_backend.cc
@@ -55,7 +55,7 @@
       // This request is not a MASQUE path.
       return false;
     }
-    masque_path = path.substr(sizeof("/.well-known/masque/") - 1);
+    masque_path = std::string(path.substr(sizeof("/.well-known/masque/") - 1));
   } else {
     if (method != "CONNECT-UDP") {
       // Unexpected method.