CVE-2025-40705 is a Cross-Site Scripting (XSS) vulnerability identified in version 8.9.0 of OpenAtlas, a software product developed by the Austrian Centre for Digital Humanities and Cultural Heritage (ACDH-CH). The vulnerability arises from improper neutralization of user input during web page generation, specifically in the handling of the "name" parameter within POST requests to the "/insert/acquisition" endpoint. Due to inadequate input validation and sanitization, an attacker can craft malicious payloads that, when submitted and subsequently rendered in the context of an authenticated user's session, execute arbitrary scripts in the victim's browser. This can lead to session cookie theft, enabling the attacker to hijack the user's session and potentially escalate privileges or perform unauthorized actions within the application. The vulnerability requires the attacker to send a specially crafted POST request and relies on the victim being authenticated and interacting with the malicious content (user interaction is required). The CVSS 4.0 base score of 5.1 (medium severity) reflects the network attack vector, low attack complexity, no privileges required by the attacker, but requiring user interaction and limited scope impact. No known exploits are currently reported in the wild, and no patches have been published at the time of this report.

For European organizations using OpenAtlas v8.9.0, particularly those involved in digital humanities and cultural heritage sectors, this vulnerability poses a risk of session hijacking and unauthorized access to sensitive data or administrative functions. The exploitation of this XSS flaw could lead to compromised user accounts, data leakage, and potential manipulation of cultural heritage data or research information. Given that OpenAtlas is used in academic and research institutions, the impact could extend to loss of data integrity and trust in digital archives. Additionally, compromised sessions could be leveraged to pivot attacks within organizational networks, increasing the risk of broader security incidents. The medium severity rating suggests a moderate risk, but the requirement for user interaction and authentication limits the attack surface somewhat. However, the cultural and academic importance of affected organizations in Europe elevates the significance of timely mitigation.

To mitigate this vulnerability, organizations should implement strict input validation and output encoding on all user-supplied data, especially the "name" parameter in the "/insert/acquisition" POST endpoint. Employing Content Security Policy (CSP) headers can help reduce the impact of XSS by restricting script execution sources. Organizations should monitor for updates or patches from ACDH-CH and apply them promptly once available. In the interim, restricting access to the affected endpoint to trusted users and networks, enforcing multi-factor authentication (MFA) to reduce the risk of session hijacking, and educating users about the risks of interacting with suspicious links or content are recommended. Additionally, web application firewalls (WAFs) with custom rules to detect and block malicious payloads targeting this parameter can provide a protective layer. Regular security assessments and penetration testing focused on XSS vulnerabilities should be conducted to identify and remediate similar issues proactively.