diff --git a/service_scan.cc b/service_scan.cc
index c42431498..e61d65383 100644
--- a/service_scan.cc
+++ b/service_scan.cc
@@ -2264,7 +2264,7 @@ static int launchSomeServiceProbes(nsock_pool nsp, ServiceGroup *SG) {
     // Check that the service is still where we left it.
     // servicescan_connect_handler can call end_svcprobe before this point,
     // putting it into services_finished already.
-    if (SG->services_remaining.front() == svc) {
+    if (!SG->services_remaining.empty() && SG->services_remaining.front() == svc) {
       // Now remove it from the remaining service list
       SG->services_remaining.pop_front();
       // And add it to the in progress list