diff --git a/server/XfrmController.cpp b/server/XfrmController.cpp
index b9a5a41..6f7bf2f 100644
--- a/server/XfrmController.cpp
+++ b/server/XfrmController.cpp
@@ -436,7 +436,7 @@
     }
 
     int optval;
-    socklen_t optlen;
+    socklen_t optlen = sizeof(optval);
     netdutils::Status status =
         getSyscallInstance().getsockopt(Fd(socket), IPPROTO_UDP, UDP_ENCAP, &optval, &optlen);
     if (status != netdutils::status::ok) {