CVE-2025-42909 is a vulnerability identified in SAP Cloud Appliance Library (CAL) Appliances, specifically in the TITANIUM_WEBAPP 4.0 version. The root cause is an insecure default profile setting in the S/4HANA appliance that results in a sensitive cookie being set without the HttpOnly flag. The HttpOnly attribute is a security feature that prevents client-side scripts from accessing cookies, thereby mitigating risks such as cross-site scripting (XSS) attacks. In this case, the absence of the HttpOnly flag means that an attacker with high privileges on one SAP CAL appliance could potentially access sensitive cookies and leverage this to gain unauthorized access to other appliances within the same environment. The vulnerability is classified under CWE-1004, which concerns sensitive cookies without the HttpOnly flag. The CVSS v3.1 base score is 3.0, indicating low severity, with the vector AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:N/A:N. This means the attack is network-based, requires high attack complexity and high privileges, no user interaction, and impacts confidentiality slightly with no impact on integrity or availability. The vulnerability affects confidentiality because sensitive cookie data could be exposed, but the impact is limited due to the high privileges required and the nature of the attack. There are no known exploits in the wild, and no patches have been released at the time of publication. The vulnerability's scope is confined to SAP CAL appliances configured with the default insecure profile, and it affects interconnected SAP environments where multiple appliances communicate or share authentication contexts. This vulnerability highlights the importance of secure cookie management and proper configuration of default profiles in enterprise cloud appliances.

For European organizations, the impact of CVE-2025-42909 is primarily a modest confidentiality risk within SAP Cloud Appliance Library environments. Organizations using SAP S/4HANA appliances deployed via SAP CAL may face the risk of sensitive cookie exposure if an attacker gains high-level privileges on one appliance. This could lead to lateral movement or unauthorized access to other SAP appliances within the same network or cloud environment. Although integrity and availability are not affected, the confidentiality breach could expose sensitive session or authentication tokens, potentially leading to further compromise if combined with other vulnerabilities or misconfigurations. The impact is mitigated by the requirement for high privileges and network access, limiting the attack surface to insiders or attackers who have already compromised an appliance. However, given the critical role of SAP systems in European enterprises—especially in sectors like manufacturing, finance, and public administration—even a low-severity vulnerability warrants attention. Failure to address this could result in compliance issues with data protection regulations such as GDPR if sensitive data is exposed. Additionally, interconnected SAP environments common in large European corporations increase the risk of cascading effects from this vulnerability.

To mitigate CVE-2025-42909 effectively, European organizations should: 1) Review and modify the default profile settings in SAP S/4HANA appliances deployed via SAP CAL to ensure that all sensitive cookies have the HttpOnly flag set, preventing client-side script access. 2) Implement strict access controls to limit high-privilege user accounts and monitor their activities closely to reduce the risk of privilege abuse. 3) Segment SAP CAL appliances network-wise to restrict lateral movement between appliances, using network segmentation and firewall rules. 4) Enable comprehensive logging and monitoring of inter-appliance communications and authentication events to detect anomalous access patterns early. 5) Regularly audit SAP CAL appliance configurations and apply security hardening best practices recommended by SAP, including reviewing cookie security attributes. 6) Stay informed about SAP security advisories and apply patches promptly once available. 7) Conduct penetration testing focused on cookie security and session management within SAP environments to identify and remediate similar weaknesses. These steps go beyond generic advice by focusing on configuration hardening, access control, and monitoring tailored to the SAP CAL appliance context.