diff --git a/tool/speed.cc b/tool/speed.cc
index a4edfe7..9f426e2 100644
--- a/tool/speed.cc
+++ b/tool/speed.cc
@@ -490,7 +490,7 @@
     return false;
   }
 
-  if (!TimeFunction(&results, [alice_msg, alice_msg_len]() -> bool {
+  if (!TimeFunction(&results, [&alice_msg, alice_msg_len]() -> bool {
         ScopedSPAKE2_CTX bob(SPAKE2_CTX_new(spake2_role_bob, kBobName,
                                             sizeof(kBobName), kAliceName,
                                             sizeof(kAliceName)));