CVE-2025-54859 is a stored cross-site scripting (XSS) vulnerability identified in NEOJAPAN Inc.'s desknet's NEO collaboration software, specifically affecting versions 9.0R2.0 and earlier. Stored XSS vulnerabilities occur when malicious scripts injected by an attacker are permanently stored on the target server, such as in databases or message boards, and then executed in the browsers of users who access the affected content. In this case, the vulnerability allows an authenticated user with high privileges to inject arbitrary JavaScript code into the application. When other users view the infected content, the malicious script executes in their browsers, potentially enabling session hijacking, credential theft, or unauthorized actions performed on behalf of the victim. The CVSS vector indicates the attack requires network access (AV:N), low attack complexity (AC:L), high privileges (PR:H), and user interaction (UI:R). The scope is changed (S:C), meaning the vulnerability affects resources beyond the initially vulnerable component. The impact on confidentiality and integrity is low (C:L, I:L), with no impact on availability (A:N). No known exploits are currently in the wild, and no official patches have been linked yet. The vulnerability was published in October 2025, with the initial reservation in September 2025 by JPCERT. This vulnerability is particularly concerning in environments where desknet's NEO is used for internal communication and collaboration, as it could allow attackers to leverage trusted sessions to escalate attacks or steal sensitive information.

For European organizations, the impact of CVE-2025-54859 can be significant in environments where desknet's NEO is deployed, particularly in sectors relying heavily on collaboration platforms such as government, finance, and large enterprises. The stored XSS vulnerability could enable attackers to execute malicious scripts in the browsers of users with access to the platform, potentially leading to session hijacking, unauthorized data access, or lateral movement within the network. Although exploitation requires high privileges and user interaction, the risk remains for insider threats or compromised high-privilege accounts. The vulnerability does not directly affect system availability but can undermine confidentiality and integrity of sensitive communications. Given the collaborative nature of desknet's NEO, exploitation could facilitate broader attacks such as phishing campaigns or malware distribution within an organization. The medium CVSS score reflects a moderate risk, but the potential for targeted attacks against critical infrastructure or sensitive data repositories in Europe elevates the importance of timely mitigation.

1. Apply official patches or updates from NEOJAPAN Inc. as soon as they become available to remediate the vulnerability. 2. Restrict high-privilege user accounts to only those necessary and enforce the principle of least privilege to reduce the risk of malicious script injection. 3. Implement strict input validation and sanitization on all user-supplied content within desknet's NEO to prevent injection of malicious scripts. 4. Deploy Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in users' browsers. 5. Conduct regular security awareness training for users, emphasizing the risks of interacting with untrusted content even within internal platforms. 6. Monitor logs and user activity for unusual behavior indicative of exploitation attempts, such as unexpected script injections or privilege escalations. 7. Consider network segmentation to isolate critical collaboration platforms and limit the spread of potential attacks. 8. Use web application firewalls (WAFs) with rules tailored to detect and block XSS payloads targeting desknet's NEO.