diff --git a/CHANGES b/CHANGES
index f58c4e6c9f..2aa2225de3 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,9 @@
+6150.	[bug]		If the zones have active upstream forwards, the
+			shutting down the server might cause assertion
+			failures as the forward were all canceled from
+			the main loop instead from the loops associated
+			with the zone. [GL #4015]
+
 6149.	[test]		As a workaround, include an OpenSSL header file before
 			including cmocka.h in the unit tests, because OpenSSL
 			3.1.0 uses __attribute__(malloc), conflicting with a
diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index 5dd59da646..0a7d1d9d5d 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -11845,6 +11845,13 @@ checkds_cancel(dns_zone_t *zone) {
 	}
 }
 
+static void
+forward_cancel_cb(void *arg) {
+	dns_request_t *request = arg;
+	dns_request_cancel(request);
+	dns_request_detach(&request);
+}
+
 static void
 forward_cancel(dns_zone_t *zone) {
 	dns_forward_t *forward;
@@ -11859,7 +11866,9 @@ forward_cancel(dns_zone_t *zone) {
 	     forward = ISC_LIST_NEXT(forward, link))
 	{
 		if (forward->request != NULL) {
-			dns_request_cancel(forward->request);
+			dns_request_t *request = NULL;
+			dns_request_attach(forward->request, &request);
+			isc_async_run(zone->loop, forward_cancel_cb, request);
 		}
 	}
 }