diff --git a/quiche/common/quiche_text_utils.cc b/quiche/common/quiche_text_utils.cc
index 5202ab3..0dd91a4 100644
--- a/quiche/common/quiche_text_utils.cc
+++ b/quiche/common/quiche_text_utils.cc
@@ -17,8 +17,8 @@
 // static
 void QuicheTextUtils::Base64Encode(const uint8_t* data, size_t data_len,
                                    std::string* output) {
-  absl::Base64Escape(std::string(reinterpret_cast<const char*>(data), data_len),
-                     output);
+  *output = absl::Base64Escape(
+      std::string(reinterpret_cast<const char*>(data), data_len));
   // Remove padding.
   size_t len = output->size();
   if (len >= 2) {