CVE-2025-40773 is a vulnerability classified under CWE-639 (Authorization Bypass Through User-Controlled Key) affecting Siemens SiPass integrated server applications in all versions prior to 3.0. The root cause is a broken access control mechanism where the server fails to adequately verify authorization for certain API requests. This allows an attacker with some level of authenticated access (low privileges) to bypass intended restrictions and manipulate data associated with other users. The vulnerability does not require user interaction and has a network attack vector with low attack complexity. While confidentiality and availability remain unaffected, the integrity of user data can be compromised, potentially leading to unauthorized changes in access control configurations or user records. No public exploits have been reported yet, but the vulnerability's presence in a widely used physical access control system raises concerns. Siemens has not yet released patches, but upgrading to version 3.0 or later is recommended once available. The vulnerability highlights the importance of robust server-side authorization checks, especially in security-critical applications like access control systems.

For European organizations, the impact primarily concerns the integrity of access control data managed by SiPass integrated. Unauthorized manipulation of user data could lead to improper access permissions, potentially allowing unauthorized physical access to sensitive facilities. This risk is particularly critical for sectors such as energy, transportation, government, and manufacturing, where Siemens access control solutions are commonly deployed. Although the vulnerability does not directly compromise confidentiality or availability, the integrity impact could indirectly facilitate insider threats or unauthorized entry, undermining physical security. The low CVSS score reflects limited direct damage potential, but the strategic importance of affected facilities in Europe elevates the operational risk. Organizations relying on SiPass integrated should consider this vulnerability in their risk assessments and incident response planning.

1. Upgrade SiPass integrated to version 3.0 or later as soon as Siemens releases a patch addressing CVE-2025-40773. 2. Until patches are available, implement strict network segmentation to isolate SiPass servers from general user networks, limiting access to trusted administrators only. 3. Enforce strong authentication and role-based access controls to minimize the number of users with privileges that could exploit this vulnerability. 4. Monitor API logs and access patterns for unusual or unauthorized requests that could indicate exploitation attempts. 5. Conduct regular audits of access control configurations and user data integrity to detect unauthorized changes promptly. 6. Engage with Siemens support for any interim mitigation guidance or workarounds. 7. Incorporate this vulnerability into security awareness training for administrators managing SiPass integrated systems.