CVE-2025-53896 is a vulnerability classified under CWE-613 (Insufficient Session Expiration) affecting Kiteworks Managed File Transfer (MFT) software versions earlier than 9.1.0. The flaw arises from a bug in the session management mechanism where user sessions do not expire properly after periods of inactivity under certain conditions. This improper session timeout can allow an attacker with access to an active session token or session context to maintain unauthorized access to the system beyond the intended session lifetime. The vulnerability impacts confidentiality and integrity by potentially allowing unauthorized users to access sensitive file transfer workflows or manipulate data without re-authentication. The CVSS 3.1 base score of 7.1 reflects a high severity, with attack vector classified as local (AV:L), requiring low privileges (PR:L), no user interaction (UI:N), and unchanged scope (S:U). The vulnerability does not affect availability. No known exploits are reported in the wild as of the publication date, but the risk remains significant due to the nature of session management flaws. The issue has been addressed in Kiteworks MFT version 9.1.0, where proper session expiration controls have been implemented to close this security gap.

For European organizations, this vulnerability poses a significant risk to the confidentiality and integrity of sensitive data handled through Kiteworks MFT, especially in sectors such as finance, healthcare, legal, and government where secure file transfer is critical. Unauthorized prolonged session access could lead to data breaches, unauthorized data manipulation, or exposure of confidential workflows. The risk is heightened in environments where shared or public workstations are used, or where session tokens might be exposed to insiders or attackers with limited access. The absence of availability impact means operational disruption is unlikely, but the potential for data compromise can have severe regulatory and reputational consequences under GDPR and other data protection frameworks prevalent in Europe.

European organizations should immediately upgrade Kiteworks MFT to version 9.1.0 or later to apply the official patch addressing this vulnerability. Beyond patching, organizations should audit session management policies to enforce strict session timeout configurations and consider implementing multi-factor authentication to reduce session hijacking risks. Monitoring and alerting on unusual session durations or concurrent sessions from the same user can help detect exploitation attempts. Network segmentation and limiting local access to the Kiteworks MFT environment can reduce the attack surface. Additionally, educating users about the importance of logging out and securing their sessions, especially on shared devices, will further mitigate risk. Regular security assessments and penetration testing focusing on session management controls are recommended to ensure ongoing protection.