An issue in open62541 v.1.5.5 and before allows a remote attacker to cause a denial of service via crafted CreateSubscription, CreateMonitoredItems(Sampling), Publish, TransferSubscriptions, and DeleteSubscriptions requests
https://github.com/open62541/open62541/issues/8092
https://github.com/open62541/open62541/blob/master/src/server/ua_subscription.h
https://github.com/open62541/open62541/blob/master/src/server/ua_subscription.c
https://github.com/open62541/open62541/blob/master/src/server/ua_services_subscription.c
https://github.com/open62541/open62541/blob/master/examples/access_control/server_access_control.c