Executive brief
open62541 is an open-source OPC UA server library used in industrial control systems and IoT applications. A remote attacker can crash OPC UA servers using specially crafted subscription management requests (CreateSubscription, CreateMonitoredItems, Publish, TransferSubscriptions, DeleteSubscriptions), causing service downtime without requiring authentication. This impacts operational technology environments relying on OPC UA for real-time data exchange.
Technical details
The vulnerability is a denial of service flaw in open62541's subscription service handler (ua_services_subscription.c). A remote attacker can trigger a crash or resource exhaustion by sending malformed OPC UA service requests related to subscription lifecycle management, including CreateSubscription, CreateMonitoredItems with sampling, Publish, TransferSubscriptions, and DeleteSubscriptions operations. The vulnerability requires network reachability to the OPC UA server but does not require authentication. No patch version information has been confirmed in the advisory, though versions 1.5.5 and earlier are affected.
Affected products
- open62541 open62541 1.5.5 and before
Timeline
- 2026-08-04: disclosed