CVE-2025-39553 is a Missing Authorization vulnerability (CWE-862) identified in the software product Church Admin developed by andy_moyle. This vulnerability affects versions up to 5.0.9, although the exact range is not fully specified (noted as 'n/a' through 5.0.9). The core issue is that certain functions or resources within Church Admin lack proper authorization checks, allowing users with limited privileges (requiring at least some level of authentication) to access or perform actions they should not be permitted to. The CVSS v3.1 base score is 4.3, indicating a medium severity level. The vector string (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N) reveals that the vulnerability is remotely exploitable over the network, requires low attack complexity, needs privileges (PR:L) but no user interaction, and impacts confidentiality to a limited extent (C:L), without affecting integrity or availability. No known exploits are currently reported in the wild, and no patches have been linked yet. This vulnerability could allow an authenticated but low-privileged user to access sensitive information or functionalities that should be restricted, potentially leading to unauthorized data disclosure within Church Admin environments. Given the nature of Church Admin as a tool likely used by religious organizations to manage member data and administrative functions, the exposure of sensitive personal or organizational data is a key concern. The lack of authorization checks could also be leveraged to enumerate data or gain insights into the system's structure or membership, which may have privacy implications.

For European organizations, particularly churches and religious institutions using Church Admin, this vulnerability could lead to unauthorized access to sensitive personal data of members, including contact details, donation records, and other private information. This unauthorized disclosure could violate the EU's General Data Protection Regulation (GDPR), leading to legal and financial repercussions. Additionally, the breach of trust and privacy could damage the reputation of affected organizations. Since the vulnerability requires some level of authentication, insider threats or compromised user accounts pose a significant risk. The impact is primarily on confidentiality, with no direct effect on data integrity or system availability. However, unauthorized data access could facilitate further social engineering or targeted attacks. The medium severity score suggests that while the vulnerability is not critical, it should be addressed promptly to prevent potential misuse and compliance violations.

Organizations using Church Admin should implement strict access control policies and monitor user privileges to minimize the risk of exploitation. Until an official patch is released, administrators should restrict user roles to the minimum necessary permissions and audit account activities regularly. Employing network segmentation and limiting access to the Church Admin application to trusted networks or VPNs can reduce exposure. Additionally, organizations should consider implementing compensating controls such as Web Application Firewalls (WAFs) to detect and block suspicious requests that attempt unauthorized access. Regularly reviewing and updating authentication mechanisms, including enforcing strong password policies and multi-factor authentication (MFA), will help mitigate risks from compromised accounts. Finally, organizations should stay informed about updates from the vendor and apply patches promptly once available.