CVE-2026-27687: SAP S/4HANA HCM Information Disclosure

CVE-2026-27687 Overview

CVE-2026-27687 is a missing authorization vulnerability affecting SAP S/4HANA HCM Portugal and SAP ERP HCM Portugal. Due to insufficient authorization checks, a user with high privileges could access sensitive data belonging to another company. This vulnerability poses a significant confidentiality risk in multi-tenant SAP environments where data isolation between companies is critical.

Critical Impact

High-privileged users can bypass authorization controls to access confidential HCM data belonging to other companies, potentially exposing sensitive employee information across organizational boundaries.

Affected Products

• SAP S/4HANA HCM Portugal
• SAP ERP HCM Portugal

Discovery Timeline

• 2026-03-10 - CVE CVE-2026-27687 published to NVD
• 2026-03-11 - Last updated in NVD database

Technical Details for CVE-2026-27687

Vulnerability Analysis

This vulnerability is classified as CWE-862 (Missing Authorization), a common weakness where the software does not perform authorization checks when accessing a resource. In the context of SAP HCM Portugal modules, the authorization framework fails to validate whether a user has proper permissions to access data belonging to a specific company code before returning sensitive HCM records.

The attack requires network access and high privileges within the SAP system, but the scope extends beyond the vulnerable component, allowing cross-company data access. While integrity and availability remain unaffected, the confidentiality impact is significant as attackers can access sensitive human capital management data including employee records, payroll information, and other HR-related data.

Root Cause

The root cause is a missing authorization check within the SAP HCM Portugal functionality. The application fails to verify company-level access permissions before allowing privileged users to retrieve HCM data, enabling unauthorized cross-company data access in multi-company SAP deployments.

Attack Vector

The vulnerability is exploitable over the network by an authenticated user with elevated privileges within the SAP system. While the attack complexity is high—requiring specific conditions and access levels—successful exploitation allows the attacker to access confidential HCM data from companies they should not have access to. This represents a horizontal privilege escalation scenario within the SAP authorization model.

The attack does not require user interaction and can be executed programmatically through SAP transactions or RFC/BAPI calls that interact with the affected HCM Portugal components.

Detection Methods for CVE-2026-27687

Indicators of Compromise

• Unusual cross-company data access patterns in SAP Security Audit Logs (SM21)
• High-privileged user accounts accessing HCM Portugal transactions for multiple company codes
• Abnormal RFC/BAPI calls targeting HCM data across organizational boundaries
• Unexpected data exports or reports containing HCM data from multiple companies

Detection Strategies

• Enable comprehensive SAP Security Audit Logging to capture authorization-related events
• Monitor SAP transaction codes related to HCM Portugal for cross-company access attempts
• Implement SAP User and Entity Behavior Analytics (UEBA) to detect anomalous data access patterns
• Review authorization objects and role assignments for HCM Portugal-related transactions

Monitoring Recommendations

• Configure alerts for high-privileged users accessing HCM data outside their assigned company codes
• Establish baseline access patterns for HCM Portugal transactions and monitor deviations
• Integrate SAP security logs with SIEM solutions for centralized monitoring
• Conduct periodic reviews of user authorizations related to cross-company HCM access

How to Mitigate CVE-2026-27687

Immediate Actions Required

• Apply the security patch referenced in SAP Note #3701020
• Review and restrict high-privileged user access to HCM Portugal transactions
• Audit current user authorizations for cross-company HCM data access
• Enable enhanced logging for HCM-related transactions until patches are applied

Patch Information

SAP has released a security update addressing this vulnerability. Organizations should apply the patch as documented in SAP Note #3701020. This update is part of the SAP Security Patch Day release cycle. Administrators should follow standard SAP transport and deployment procedures when applying the fix.

Workarounds

• Restrict the assignment of high-privilege roles that grant access to HCM Portugal functionality
• Implement compensating authorization controls to enforce company-level data segregation
• Limit network access to SAP systems containing sensitive HCM data
• Consider implementing SAP's Authorization Trace (ST01) to monitor and audit authorization checks

# Example: Enable SAP Security Audit Log for authorization monitoring
# Transaction SM19 - Configure Security Audit parameters
# Enable logging for authorization checks and data access events
# Filter: Event Class = Dialog, RFC, and Authorization Check
# Set filter for specific user groups with elevated privileges