S2OPC through 1.7.3 contains a null pointer dereference in msg_subscription_publish_bs__alloc_notification_message_items() where a failed allocation for DataChangeNotification is overwritten by a successful allocation for EventNotificationList. Attackers can trigger heap allocation failures on sessions with both data-change and event notifications to cause the server process to terminate.
https://gitlab.com/systerel/S2OPC/-/merge_requests/1862
https://gitlab.com/systerel/S2OPC/-/issues/1815
https://gitlab.com/systerel/S2OPC/-/commit/8848f051eed069b107ae7cb16a346d6f6386a8f5
Published: 2026-09-13
Updated: 2026-09-13
Base Score: 4.9
Vector: CVSS2#AV:N/AC:H/Au:S/C:N/I:N/A:C
Severity: Medium
Base Score: 5.3
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity: Medium
Base Score: 6
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: Medium