CVE-2025-53900: Kiteworks MFT Privilege Escalation Flaw

CVE-2025-53900 Overview

CVE-2025-53900 is a privilege escalation vulnerability in Kiteworks Managed File Transfer (MFT), a platform that orchestrates end-to-end file transfer workflows. The flaw stems from an unfavourable definition of roles and permissions when managing Connections. Authorized users can leverage the weak privilege model to escalate access beyond their intended role. The issue affects all versions prior to 9.1.0 and is tracked under [CWE-267: Privilege Defined With Unsafe Actions]. Kiteworks resolved the flaw in version 9.1.0. The vulnerability requires network access and low-privilege authentication, and successful exploitation impacts confidentiality, integrity, and availability of the file transfer environment.

Critical Impact
Authenticated users with low privileges can escalate access through Connection management, enabling unauthorized control over file transfer workflows and sensitive data in transit.

Affected Products

Accellion Kiteworks Managed File Transfer versions prior to 9.1.0
Kiteworks MFT deployments exposing Connection management to authenticated users
All Kiteworks MFT instances using default role and permission definitions

Discovery Timeline

2025-11-29 - CVE-2025-53900 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-53900

Vulnerability Analysis

CVE-2025-53900 is a privilege escalation flaw rooted in how Kiteworks MFT defines roles and permissions for managing Connections. Connections represent the endpoints and credentials used to move files between systems. The permission model does not sufficiently restrict which authorized users can create, modify, or invoke privileged Connection operations. As a result, a user with limited access can perform actions that should require elevated privileges. This weakness maps to [CWE-267], where a defined role is granted actions that carry unsafe security implications.

Root Cause

The root cause is an improper mapping between user roles and the actions permitted on Connection objects. The application authorizes Connection management operations based on role membership rather than granular, action-level checks. Low-privileged authorized users inherit capabilities intended for administrators.

Attack Vector

An attacker must first obtain valid credentials for the Kiteworks MFT interface. Using those credentials, the attacker interacts with Connection management functions over the network. By invoking Connection operations that lack proper permission enforcement, the attacker gains privileges beyond their assigned role. This can lead to unauthorized access to files handled by the MFT platform, tampering with transfer workflows, and disruption of file transfer services. No verified public exploit or proof-of-concept is currently available. See the Kiteworks GitHub Security Advisory for vendor technical details.

Detection Methods for CVE-2025-53900

Indicators of Compromise

Unexpected creation or modification of Connection definitions by non-administrative accounts
Authentication events followed by administrative actions from users lacking corresponding role assignments
Anomalous file transfer jobs referencing Connections not authorized by change management
Audit log entries showing permission-sensitive Connection operations executed by standard users

Detection Strategies

Baseline Connection management activity per user role and alert on deviations
Correlate MFT audit logs with identity provider events to detect privilege mismatches
Review role-to-action mappings in Kiteworks audit exports for evidence of low-privilege users performing privileged operations

Monitoring Recommendations

Forward Kiteworks MFT audit logs to a centralized logging platform for continuous review
Monitor administrative API endpoints related to Connection creation, editing, and credential updates
Track authentication sessions that touch Connection management within short time windows after login
Alert on outbound transfers to new or recently modified Connection targets

How to Mitigate CVE-2025-53900

Immediate Actions Required

Upgrade Kiteworks MFT to version 9.1.0 or later without delay
Review all Connection definitions and remove entries created by unauthorized or unexpected accounts
Audit user role assignments and revoke access for accounts that do not require Connection management
Rotate credentials stored in Connections that may have been exposed or modified

Patch Information

Kiteworks addressed CVE-2025-53900 in Kiteworks MFT version 9.1.0. The patch corrects the role and permission definitions governing Connection management. Refer to the Kiteworks GitHub Security Advisory GHSA-gjq3-8v6p-2h6h for upgrade instructions and vendor guidance.

Workarounds

Restrict access to the Kiteworks MFT administrative interface to a limited set of trusted network sources
Enforce least privilege by removing Connection management permissions from non-administrative roles until the upgrade is applied
Enable enhanced audit logging on all Connection-related operations to support incident review
Require multi-factor authentication for all Kiteworks MFT accounts to raise the barrier for credential-based abuse

bash

# Verify current Kiteworks MFT version and confirm upgrade to 9.1.0 or later
kiteworks-admin --version

# Example: restrict admin interface to trusted networks (iptables reference)
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP