CVE-2026-27678

The vulnerability resides in the SAP S/4HANA backend OData Service for Manage Reference Structures. Due to missing authorization checks, the service fails to verify that a user has the necessary permissions before allowing updates or deletions of child entities. This is a classic access control flaw means that any user who can reach the exposed OData endpoint can manipulate data without proper entitlement validation [1].

Exploitation requires network access to the exposed OData service. No special privileges are needed because the authorization check is absent entirely. An attacker can send crafted HTTP requests to the service's endpoints to update or delete child entities that should be protected. The attack surface is the OData interface, which is typically exposed for integration scenarios [1].

Successful exploitation results in unauthorized modification or deletion of child reference structures. This has a high impact on data integrity, as an attacker could corrupt business-critical reference data used in SAP S/4HANA processes. Confidentiality and availability are not affected, meaning the attacker cannot read data remains readable and the service remains operational [1].

SAP has released a security note as part of its monthly Security Patch Day to address this issue. Customers are strongly advised to apply the provided patch or update to the latest support package that includes the fix. No workaround is mentioned; the only mitigation is to install the security update [1].