Key points
- CVE-2026-89107 carries a CVSS score of 9.9, rated as critical severity.
- The flaw exists in the Manage Substitution/Validation Rules component of SAP S/4HANA.
- Affected versions include S4CORE 105, 106, 107, and 108.
The short version
- An authenticated attacker with specific business privileges can exploit this vulnerability.
- Specially crafted input is interpreted as executable ABAP code by the rule processing logic.
- Successful exploitation results in full compromise of the affected system.
The details
The National Vulnerability Database records CVE-2026-89107 as a critical security flaw within SAP S/4HANA systems. The vulnerability stems from insufficient input validation in the Manage Substitution/Validation Rules functionality. This component processes rule definitions using a domain-specific scripting language. According to the NVD record, the weakness is classified under CWE-94, which relates to code injection issues.
An attacker who has already gained authentication and possesses specific business privileges can submit specially crafted input to the system. The rule processing logic fails to adequately sanitise this input. Consequently, the system interprets the malicious data as executable ABAP code. This allows the attacker to run arbitrary code within the SAP environment.
The impact of this exploitation is severe. The NVD states that successful abuse leads to full compromise of the affected system. This results in high impact on the confidentiality, integrity, and availability of the system. The flaw affects SAP S/4HANA versions S4CORE 105, 106, 107, and 108. No patch or fix has been confirmed yet in the provided source material.
The context
This issue highlights the risks associated with domain-specific scripting languages in enterprise software. When input validation is weak, these languages can become vectors for code injection. The requirement for specific business privileges suggests that attackers must first breach initial access controls. However, once inside, the potential for lateral movement and full system takeover is significant.
Organisations running the affected S4CORE versions are exposed to this risk. The critical CVSS score of 9.9 indicates that the vulnerability has a high impact. Security teams should prioritise assessing their exposure to this flaw. Monitoring for unusual ABAP code execution may help detect attempts to exploit this weakness.
Defender's checklist
- Verify if your SAP S/4HANA instance runs S4CORE versions 105 through 108.
- Review access controls for users with privileges to manage substitution rules.
- Monitor logs for unexpected ABAP code execution or rule definition changes.
- Prepare incident response plans for potential full system compromise scenarios.
What to do and how to stay safe: SAP S/4HANA
- Audit user accounts with access to the Manage Substitution/Validation Rules feature.
- Implement strict input validation checks for any custom rule definitions.
- Monitor system logs for anomalous ABAP code execution patterns.
- Once the vendor provides an update, apply it immediately to affected systems.
Step-by-step guide: Unpatched Software: Why Missing Updates Create Hidden Entry Points
General security guidance from the Cipher Insider newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
What is the CVSS score for CVE-2026-89107?
The National Vulnerability Database rates CVE-2026-89107 with a CVSS score of 9.9, which is considered critical.
Which SAP S/4HANA versions are affected by this vulnerability?
The flaw affects SAP S/4HANA S4CORE versions 105, 106, 107, and 108, specifically in the Manage Substitution/Validation Rules component.
Can an unauthenticated attacker exploit this vulnerability?
No, the source material states that an authenticated attacker with specific business privileges is required to exploit this flaw.
