diff --git a/libtransmission/rpc-server.c b/libtransmission/rpc-server.c
index 7414106ef..7d1450f84 100644
--- a/libtransmission/rpc-server.c
+++ b/libtransmission/rpc-server.c
@@ -229,6 +229,8 @@ tr_rpcSetACL( tr_rpc_server * server, const char * acl, char ** setme_errmsg )
     {
         if( setme_errmsg )
             *setme_errmsg = errmsg;
+        else
+            tr_free( errmsg );
         ret = -1;
     }
     else