diff --git a/CHANGES b/CHANGES
index a56059ca87..30baddeefe 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+5183.	[bug]		Reinitialize ECS data before reusing client
+			structures. [GL #881]
+
 5182.	[bug]		Fix a high-load race/crash in handling of
 			isc_socket_close() in resolver. [GL #834]
 
diff --git a/lib/ns/client.c b/lib/ns/client.c
index 321818bd27..4a43fb6d32 100644
--- a/lib/ns/client.c
+++ b/lib/ns/client.c
@@ -765,6 +765,7 @@ ns_client_endrequest(ns_client_t *client) {
 	client->udpsize = 512;
 	client->extflags = 0;
 	client->ednsversion = -1;
+	dns_ecs_init(&client->ecs);
 	dns_message_reset(client->message, DNS_MESSAGE_INTENTPARSE);
 
 	if (client->recursionquota != NULL) {