CVE-2021-25966 is a high-severity vulnerability affecting OrchardCore CMS versions from 1.0.0-beta1-3383 up to 1.0.0. The issue stems from insufficient session expiration controls (CWE-613) within the OrchardCore Users module. Specifically, when a user or administrator changes a password, existing authenticated sessions for that user are not invalidated or terminated. This means that any session active prior to the password change remains valid, allowing continued access to the application despite the password update. The vulnerability arises due to improper session management logic that fails to enforce session revocation upon credential changes. Exploitation requires no privileges beyond user-level access and only user interaction to trigger the password change. The CVSS 3.1 base score is 8.8 (high), reflecting the network attack vector, low attack complexity, no privileges required, user interaction required, and high impact on confidentiality, integrity, and availability. The vulnerability can lead to unauthorized persistent access by an attacker or malicious insider who has gained access to a session token before a password reset, effectively bypassing the intended security control of password changes to terminate sessions. Although no known exploits are currently reported in the wild, the vulnerability presents a significant risk to organizations using affected OrchardCore versions, especially where sensitive data or critical services are managed through the CMS. The lack of session invalidation undermines the security benefits of password changes and can facilitate lateral movement or prolonged unauthorized access within the system.

For European organizations deploying OrchardCore CMS in the affected versions, this vulnerability poses a critical risk to user account security and overall system integrity. Attackers or insiders who have compromised session tokens can maintain access even after password resets, potentially leading to data breaches, unauthorized content manipulation, or disruption of services. This is particularly concerning for organizations handling sensitive personal data under GDPR, as unauthorized access could result in data exposure and regulatory penalties. The vulnerability also undermines incident response processes, as password changes are a common remediation step to revoke access. The persistence of sessions post-password change can delay detection and containment of breaches. Additionally, the integrity of website content and availability of services managed by OrchardCore could be compromised, impacting business continuity and reputation. Given the high CVSS score and the critical nature of session management in access control, European enterprises using OrchardCore CMS should prioritize addressing this vulnerability to maintain compliance and security posture.

1. Upgrade OrchardCore CMS to a version beyond 1.0.0 where this vulnerability is fixed, or apply vendor-provided patches if available. 2. Implement custom session management logic to forcibly invalidate all active sessions upon password changes if upgrading is not immediately feasible. This can be done by tracking session tokens with timestamps and comparing them against the last password change time. 3. Enforce multi-factor authentication (MFA) to reduce the risk of session token misuse. 4. Monitor active sessions and implement session timeout policies to limit session lifetime. 5. Conduct regular audits of user sessions and access logs to detect anomalous persistent sessions. 6. Educate users and administrators on the importance of logging out and session hygiene, especially after password changes. 7. If possible, integrate additional security controls such as Web Application Firewalls (WAF) to detect suspicious session activities. 8. Review and enhance incident response plans to include checks for session persistence after credential changes.