CVE-2025-66581 is an authorization bypass vulnerability classified under CWE-863 affecting Frappe Learning Management System (LMS) versions before 2.41.0. The root cause is improper enforcement of server-side authorization controls, where the system relied heavily on client-side or UI-level permission checks. This design flaw allowed authenticated users with minimal privileges, such as students, to bypass role restrictions by directly invoking API endpoints intended for instructors or administrators. As a result, these users could perform unauthorized actions across multiple LMS features, potentially modifying content, accessing restricted data, or altering administrative settings. The vulnerability does not require user interaction beyond authentication and can be exploited remotely over the network. Despite the potential for privilege escalation within the LMS, the CVSS 4.0 base score is low (1.3) due to limited impact on confidentiality and availability, and the requirement for authenticated access. No known public exploits or active exploitation have been reported. The issue was addressed in Frappe LMS version 2.41.0 by implementing proper server-side authorization checks to enforce role-based access controls consistently across all endpoints.

For European organizations, particularly educational institutions, universities, and corporate training providers using Frappe LMS, this vulnerability could allow unauthorized privilege escalation within their learning platforms. Attackers with low-level user accounts could manipulate course content, access sensitive instructional materials, or interfere with administrative functions, potentially undermining the integrity and trustworthiness of the LMS environment. While the vulnerability does not directly expose sensitive personal data or cause system-wide outages, unauthorized modifications could disrupt learning activities and damage institutional reputation. The impact is more significant in environments where LMS content controls certification, compliance training, or critical operational knowledge. Given the low CVSS score and lack of known exploits, the immediate risk is limited but should not be ignored, especially in regulated sectors requiring strict access controls.

European organizations should promptly upgrade all Frappe LMS instances to version 2.41.0 or later to remediate this vulnerability. Until patched, administrators should restrict LMS access to trusted users and monitor for unusual API activity indicative of privilege abuse. Implement network-level access controls to limit exposure of LMS APIs to internal or VPN-only access. Conduct regular audits of user roles and permissions to ensure no unauthorized privilege escalation has occurred. Additionally, review and harden server-side authorization logic in custom LMS extensions or integrations to prevent similar flaws. Employ logging and alerting on sensitive LMS operations to detect potential misuse early. Finally, educate users about the importance of using only official LMS interfaces and discourage direct API manipulation.