IBM App Connect Enterprise versions 13.0.1.0 through 13.0.8.0 and 12.0.1.0 through 12.0.12.27 contain a vulnerability that allows a local attacker to execute arbitrary code via insecure deserialization. This vulnerability is identified as CVE-2026-17156 and has a high severity rating with a CVSS score of 7.8. The flaw arises from improper handling of serialized data, which can be exploited to compromise confidentiality, integrity, and availability of the affected system.