CVE-2025-40707 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). This vulnerability arises due to improper neutralization of user input during web page generation, specifically when processing POST requests to the "/insert/place" endpoint. The parameters "name" and "alias-0" do not adequately validate or sanitize input, allowing an attacker to inject malicious scripts. When an authenticated user interacts with a crafted query exploiting this flaw, the injected script can execute in their browser context, potentially stealing session cookies or performing other unauthorized actions on behalf of the user. The vulnerability requires the attacker to send a specially crafted POST request and relies on user interaction (the victim must be authenticated and visit the maliciously crafted page). The CVSS v4.0 base score is 5.1, indicating a medium severity level, with characteristics including network attack vector, low attack complexity, no privileges required for the attacker, but user interaction is necessary. The vulnerability does not impact confidentiality, integrity, or availability directly but compromises session security through cookie theft, which can lead to session hijacking. No known exploits are currently reported in the wild, and no patches are listed yet. The vulnerability is classified under CWE-79, which covers improper neutralization of input leading to XSS attacks.

For European organizations, especially those involved in digital humanities, cultural heritage, or academic research using OpenAtlas, this vulnerability poses a risk of session hijacking and unauthorized actions performed under the guise of legitimate users. The impact includes potential data exposure within user sessions, unauthorized data manipulation, and reputational damage if user accounts are compromised. Since OpenAtlas is used in cultural heritage contexts, unauthorized access could lead to manipulation or theft of sensitive cultural data or research information. The medium severity score reflects that while the vulnerability does not directly compromise system-wide confidentiality or availability, it can be leveraged to escalate privileges or gain unauthorized access through session theft. Organizations with multiple authenticated users are at higher risk, as attackers can target any user with sufficient privileges. The lack of known exploits reduces immediate risk but does not eliminate the threat, especially if attackers develop exploits post-disclosure. Additionally, the need for user interaction means phishing or social engineering could be used to lure users into triggering the vulnerability.

European organizations using OpenAtlas 8.9.0 should immediately review and restrict access to the "/insert/place" endpoint, especially limiting POST requests to trusted users and networks. Implementing Web Application Firewalls (WAFs) with rules to detect and block suspicious input patterns targeting the "name" and "alias-0" parameters can provide interim protection. Organizations should enforce strict Content Security Policies (CSP) to reduce the impact of any injected scripts. User training to recognize phishing attempts and suspicious links is critical to prevent exploitation via social engineering. Monitoring web server logs for unusual POST requests to the vulnerable endpoint can help detect attempted exploitation. Since no official patch is currently available, organizations should engage with ACDH-CH for updates and consider code-level input validation and sanitization improvements as a custom mitigation. Additionally, session management should be hardened by setting HttpOnly and Secure flags on cookies to reduce the risk of cookie theft via XSS. Regular security assessments and penetration testing focusing on XSS vulnerabilities in OpenAtlas deployments are recommended.