CVE-2026-23687 is a vulnerability classified under CWE-347 (Improper Verification of Cryptographic Signature) affecting SAP NetWeaver Application Server ABAP and ABAP Platform. The issue arises because the system improperly verifies cryptographic signatures on signed XML documents. An authenticated attacker with normal user privileges can obtain a valid signed message and then modify the signed XML document before sending it to the verifier. Due to the flawed signature verification, the system may accept these tampered documents as legitimate. This can lead to acceptance of falsified identity information, enabling unauthorized access to sensitive user data and potentially disrupting normal system operations. The vulnerability spans a wide range of SAP_BASIS versions from 700 to 918, indicating a long-standing issue across multiple releases. The CVSS v3.1 score of 8.8 indicates a high severity, with network attack vector, low attack complexity, privileges required but no user interaction, and high impact on confidentiality, integrity, and availability. Although no exploits are currently known in the wild, the vulnerability’s nature makes it a significant risk for organizations relying on SAP NetWeaver AS ABAP. The flaw could be exploited to bypass authentication controls or escalate privileges by manipulating identity assertions within signed XML messages, which are commonly used in SAP for secure communication and authorization. This vulnerability highlights the critical importance of robust cryptographic signature verification in enterprise software platforms.

For European organizations, the impact of CVE-2026-23687 is substantial due to the widespread use of SAP NetWeaver AS ABAP in enterprise resource planning (ERP), supply chain management, and other critical business functions. Exploitation could lead to unauthorized disclosure of sensitive personal and corporate data, violating GDPR and other data protection regulations, resulting in legal and financial penalties. The ability to tamper with identity information may allow attackers to impersonate legitimate users, leading to fraudulent transactions, data manipulation, or disruption of business processes. Availability impacts could cause operational downtime, affecting business continuity. Given SAP’s integral role in many European industries such as manufacturing, finance, and public sector, the vulnerability poses a risk to national critical infrastructure and economic stability. The high CVSS score reflects the potential for severe confidentiality, integrity, and availability breaches. Organizations may face reputational damage and loss of customer trust if exploited. The lack of known exploits currently provides a window for proactive mitigation, but the vulnerability’s presence in many SAP versions increases the attack surface.

1. Apply official SAP security patches and updates as soon as they are released to address CVE-2026-23687. Monitor SAP Security Notes and advisories regularly. 2. Restrict access to SAP NetWeaver AS ABAP systems to trusted users and networks only, using network segmentation and strong access controls. 3. Implement strict authentication and authorization policies to limit the privileges of users, minimizing the risk from compromised accounts. 4. Monitor logs and audit trails for unusual activity involving signed XML documents, such as unexpected modifications or signature verification failures. 5. Employ additional cryptographic validation layers or integrity checks on XML messages where possible to detect tampering. 6. Conduct regular security assessments and penetration testing focused on SAP environments to identify potential exploitation attempts. 7. Educate SAP administrators and developers about secure handling of cryptographic signatures and the risks of improper verification. 8. Consider deploying runtime application self-protection (RASP) or web application firewalls (WAFs) with SAP-specific rules to detect and block suspicious XML document manipulations. 9. Maintain an incident response plan tailored to SAP security incidents to quickly contain and remediate any exploitation. 10. Coordinate with SAP support and cybersecurity vendors for threat intelligence and mitigation best practices.