CVE-2026-0509 is a critical security vulnerability classified under CWE-862 (Missing Authorization) affecting SAP NetWeaver Application Server ABAP and ABAP Platform. The flaw allows an authenticated user with low privileges to bypass the required S_RFC authorization checks when performing background Remote Function Calls (RFCs). RFCs are mechanisms used within SAP environments to enable communication and execution of functions across systems. Normally, executing background RFCs requires specific authorization (S_RFC) to prevent unauthorized actions. However, due to this vulnerability, the authorization check is improperly enforced, allowing low-privileged users to invoke background RFCs that they should not be permitted to execute. This can lead to unauthorized changes in system state, data corruption, or disruption of critical business processes, impacting the integrity and availability of the affected SAP systems. The vulnerability affects multiple versions of SAP NetWeaver, including kernel versions 7.22, 7.53, 7.54, 7.77, 7.89, 7.93, and ABAP Platform versions 9.16, 9.18, and 9.19, indicating a wide attack surface. The CVSS v3.1 base score is 9.6, reflecting a critical severity with network attack vector, low attack complexity, requiring privileges but no user interaction, and scope change. No known exploits have been reported in the wild yet, but the potential impact is severe. The vulnerability does not affect confidentiality, meaning sensitive data leakage is unlikely, but the integrity and availability impacts could disrupt business operations significantly. SAP has not yet published patches at the time of this report, so organizations must implement compensating controls to mitigate risk.

For European organizations, the impact of CVE-2026-0509 can be substantial given the widespread use of SAP NetWeaver in critical sectors such as manufacturing, finance, utilities, and public administration. Exploitation could allow attackers or malicious insiders to execute unauthorized background processes, potentially altering business-critical data or causing system outages. This can lead to operational disruptions, financial losses, regulatory non-compliance, and reputational damage. Since the vulnerability affects integrity and availability but not confidentiality, the primary risks involve data tampering and denial of service rather than data breaches. The requirement for authentication limits exposure to internal or compromised users, but given the complexity of SAP environments and the possibility of credential theft, the threat remains significant. European organizations with complex SAP landscapes and interconnected systems may face cascading effects if unauthorized RFCs propagate changes across integrated modules. Additionally, the critical infrastructure and manufacturing sectors in Europe, which heavily depend on SAP for supply chain and production management, are particularly vulnerable to operational disruptions caused by this flaw.

1. Apply SAP security patches immediately once they become available for the affected versions to address the missing authorization check. 2. Until patches are released, restrict user permissions rigorously by reviewing and minimizing the assignment of S_RFC and related authorizations to only trusted and necessary users. 3. Implement strict segregation of duties (SoD) policies to prevent low-privileged users from gaining access to sensitive RFC functions. 4. Monitor and audit RFC usage logs continuously to detect unusual or unauthorized background RFC calls, enabling rapid incident response. 5. Employ network segmentation and firewall rules to limit access to SAP NetWeaver systems, especially restricting access to RFC interfaces from untrusted networks or users. 6. Use SAP’s security notes and guidelines to harden the system configuration and disable unnecessary RFC services or functions. 7. Conduct regular security awareness training for SAP administrators and users about the risks of privilege misuse and the importance of credential protection. 8. Consider deploying runtime application self-protection (RASP) or SAP-specific security monitoring tools that can detect and block unauthorized RFC invocations in real time.