CVE-2025-53939 is a vulnerability classified under CWE-20 (Improper Input Validation) affecting Kiteworks private data network (PDN) products prior to version 9.1.0. The flaw arises during the management of roles assigned to shared folders within the system. Specifically, the input validation mechanisms fail to properly verify or sanitize role modification requests, which can result in an attacker with legitimate but limited privileges unexpectedly elevating another user's permissions on a shared folder. This elevation can grant unauthorized access or administrative capabilities over sensitive shared data. The vulnerability is exploitable remotely over the network (AV:N), requires low privileges (PR:L), and does not require user interaction (UI:N). The scope is unchanged (S:U), meaning the impact is confined to the vulnerable component. The CVSS v3.1 base score is 6.3, reflecting a medium severity with impacts on confidentiality, integrity, and availability (C:L/I:L/A:L). Although no public exploits have been reported, the vulnerability poses a risk of privilege escalation within organizations using Kiteworks PDN. The vendor addressed the issue in version 9.1.0 by implementing proper input validation controls to prevent unauthorized role changes. Organizations running versions older than 9.1.0 are vulnerable and should prioritize patching. The vulnerability's nature suggests that attackers could manipulate role assignments to gain elevated access rights, potentially leading to data exposure or disruption of data sharing workflows.

For European organizations, this vulnerability could lead to unauthorized access to sensitive shared data, undermining confidentiality and integrity of critical information. The ability to elevate permissions on shared folders may allow attackers to exfiltrate data, modify or delete files, or disrupt collaboration workflows. This is particularly impactful for sectors handling sensitive or regulated data such as finance, healthcare, government, and legal services. Since Kiteworks is often used for secure file sharing and data governance, exploitation could result in compliance violations with GDPR and other data protection regulations, leading to legal and financial repercussions. The medium severity score indicates a significant but not critical risk; however, the ease of exploitation combined with the potential for privilege escalation means organizations must act promptly. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially from targeted attackers. The vulnerability could also be leveraged as a foothold for further lateral movement within networks.

1. Immediately upgrade all Kiteworks PDN installations to version 9.1.0 or later where the vulnerability is patched. 2. Conduct a thorough audit of shared folder permissions and role assignments to detect and remediate any unauthorized changes or suspicious privilege escalations. 3. Implement strict network segmentation and access controls to limit who can access the Kiteworks management interfaces, ideally restricting to trusted administrative networks or VPNs. 4. Enable detailed logging and monitoring of role management activities to detect anomalous behavior indicative of exploitation attempts. 5. Educate administrators and users about the risks of improper role assignments and enforce the principle of least privilege. 6. Review and update incident response plans to include scenarios involving privilege escalation within file sharing platforms. 7. If immediate patching is not possible, consider temporary compensating controls such as disabling role management features or restricting role changes to a minimal set of trusted administrators. 8. Coordinate with Kiteworks support for any additional security advisories or recommended configurations.