CVE-2026-27688: SAP NetWeaver Privilege Escalation Flaw

CVE-2026-27688 Overview

CVE-2026-27688 is a missing authorization check vulnerability in SAP NetWeaver Application Server for ABAP. An authenticated attacker with user-level privileges can invoke a specific Remote Function Call (RFC) function module to read Database Analyzer log files. The flaw maps to [CWE-862: Missing Authorization] and exposes sensitive operational data stored in those logs. Integrity and availability of the SAP system are not affected, but the disclosed log content can support privilege escalation and reconnaissance for follow-on attacks.

Critical Impact

Authenticated SAP users can read Database Analyzer log files via an RFC function module, exposing sensitive diagnostic data and enabling further privilege escalation paths.

Affected Products

• SAP NetWeaver Application Server for ABAP
• SAP systems exposing the affected RFC function module
• Refer to SAP Note #3704740 for the authoritative list of affected releases

Discovery Timeline

• 2026-03-10 - CVE-2026-27688 published to NVD
• 2026-03-11 - Last updated in NVD database
• 2026-03-10 - SAP releases security note as part of SAP Security Patch Day

Technical Details for CVE-2026-27688

Vulnerability Analysis

The vulnerability resides in an RFC-callable function module within SAP NetWeaver Application Server for ABAP. The function module exposes Database Analyzer log file content to callers without verifying that the caller holds the required authorization object. Database Analyzer logs capture database performance traces and diagnostic events. These records can include SQL fragments, schema references, and operational metadata useful to an attacker performing reconnaissance.

Because the function module is reachable over RFC, any authenticated user with rights to call the module can retrieve the log content. The vulnerability allows a low-privileged user to read data normally restricted to administrative roles. The impact is scoped to confidentiality, with no modification or denial-of-service consequences.

Root Cause

The root cause is the absence of an AUTHORITY-CHECK statement guarding the log file read operation inside the RFC function module. SAP authorization model requires explicit authority checks on sensitive operations. Without that check, the ABAP runtime grants access based solely on the caller's ability to execute the module, bypassing role-based access control on the log data itself.

Attack Vector

The attack vector is network-based and requires valid SAP credentials with permission to execute the affected RFC function module. The attacker connects to the SAP system via an RFC client such as sapnwrfc, JCo, or an ABAP report using CALL FUNCTION ... DESTINATION. The attacker invokes the vulnerable function module and receives Database Analyzer log content in the response. No user interaction is required, and the scope changes because the disclosed data belongs to a different security context than the caller.

No public proof-of-concept exploit is available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. Detailed technical disclosure is restricted by SAP and available to customers through SAP Note #3704740.

Detection Methods for CVE-2026-27688

Indicators of Compromise

• Unexpected RFC calls from low-privileged user accounts targeting Database Analyzer or DBACOCKPIT-related function modules
• Security Audit Log (SM20) entries showing RFC function module execution by users outside the database administrator role
• Unusual outbound RFC traffic patterns from application servers to external systems following authenticated user sessions

Detection Strategies

• Enable and monitor the SAP Security Audit Log for RFC function module calls, filtering on the function modules listed in SAP Note #3704740
• Correlate RFC execution events with user role assignments to flag callers who lack the expected administrative authorizations
• Baseline normal RFC usage per user and alert on deviations, particularly bulk reads of diagnostic or log-related modules

Monitoring Recommendations

• Forward SAP audit logs and gateway logs to a centralized SIEM for correlation with identity and endpoint telemetry
• Track authorization object usage with transaction STAUTHTRACE to identify function modules that read sensitive data without authority checks
• Review SM19/RSAU_CONFIG audit profiles to ensure RFC and sensitive function module execution events are recorded

How to Mitigate CVE-2026-27688

Immediate Actions Required

• Apply the SAP security patch referenced in SAP Note #3704740 on all SAP NetWeaver AS ABAP systems
• Review and restrict the S_RFC authorization object to limit which users can execute the affected function module and function group
• Audit user role assignments to confirm only authorized administrators retain access to Database Analyzer and database monitoring functions

Patch Information

SAP released a fix as part of SAP Security Patch Day. Customers must download and apply the support package or correction instructions listed in SAP Note #3704740. The patch introduces the missing authorization check inside the affected RFC function module.

Workarounds

• Remove execution rights on the affected function module from end-user roles until the patch is applied
• Restrict RFC gateway access using reginfo and secinfo configuration files to block untrusted RFC clients
• Enforce network segmentation between business users and SAP application servers to limit who can initiate RFC sessions

# Example: tighten S_RFC authorization in PFCG for the affected function group
# Transaction: PFCG -> edit role -> Authorizations
# Object: S_RFC
#   ACTVT  = 16 (Execute)
#   RFC_TYPE = FUGR
#   RFC_NAME = <affected_function_group>  # restrict to admin roles only
# Then regenerate the profile and run SUPC to propagate changes.