Act nowDisclosed

Advisory · CVE-2026-89107

ABAP code injection in SAP S/4HANA substitution and validation rules

SAP S/4HANA's Manage Substitution/Validation Rules does not sufficiently validate input for its domain-specific scripting language, letting an authenticated attacker get input interpreted as ABAP code and fully compromise the system. SAP rates it CVSS 3.1 9.9.

Advisory published October 13, 2026Independent summary
Vendor
SAP
Product
S/4HANA
Identifier / CWE
CVE-2026-89107
CWE-94
Action timing
Immediate
ELI5

Explain it like I’m five

A business rule box in S/4HANA accepts text that the system then runs as ABAP code, so a crafted rule becomes a program the ERP executes.

SIMPLIFIED_ATTACK_PATH03 STEPS
  1. 01Business privileges

    An attacker with specific business privileges opens the substitution or validation rule function.

  2. 02Crafted rule input

    The attacker submits input written in the rule scripting language that escapes into ABAP.

  3. 03ABAP executes

    The rule processing logic interprets the input as executable ABAP code, fully compromising the system.

What happened

SAP disclosed CVE-2026-89107 for S/4HANA (Manage Substitution/Validation Rules), affecting S4CORE 105 through 109. Input processed by the rule definition functionality, which uses a domain-specific scripting language, is not sufficiently validated and can be interpreted as executable ABAP code (CWE-94). SAP says successful exploitation means full compromise of the affected system and scores it 9.9.

Apply SAP note 3805589 through the normal SAP patch process; this advisory does not name a fixed version beyond the note.

What to do

  1. Inventory every S/4HANA deployment, including test, training, and individually managed instances.
  2. Apply the vendor fix or upgrade exactly as directed in the linked vendor bulletin or advisory.
  3. Restrict network access to S/4HANA while remediation is underway, especially for internet-facing instances.
  4. Review application and server logs for new or changed substitution and validation rules, unexpected ABAP objects, and rule edits by users who do not normally maintain them.
  5. Check for accounts, content, or configuration created outside normal change processes, and rotate exposed credentials where access cannot be ruled out.
  6. Verify the deployed version or patch level after remediation.

Management note

S/4HANA is the financial system of record for many companies. A 9.9 code injection reachable with business privileges belongs at the top of the patch queue, with a rule-change audit behind it.