ACCORDING to ABB PSIRT SA25P004 republished by CISA, ABB B&R Automation Studio contains a vulnerability affecting Automation Studio <6.5, 6.5 (CVE-2025-11043) that could allow an unauthenticated attacker on the network to masquerade as a trusted party when the software connects to a server via ANSL over TLS or OPC-UA. The advisory notes a CVSS v3.1 base score of 7.4 (HIGH) for an Improper Certificate Validation vulnerability in the OPC-UA client and ANSL over TLS client.
An update is available that resolves the vulnerability, with ABB stating the problem is corrected in B&R Automation Studio version 6.5; customers are advised to apply the update at earliest convenience. Mitigation guidance includes that an attacker would need to intercept and redirect communications and present manipulated certificates, and ABB recommends operating Automation Studio within Level 2 of the ABB ICS Cyber Security Reference Architecture when connecting to Level 1 devices via ANSL over TLS or OPC-UA.
The advisory also notes that ABB PSIRT reported the vulnerability to CISA, and that the notice includes standard legal and defensive guidance.