CVE-2023-41708 is a medium-severity cross-site scripting (XSS) vulnerability affecting the Open-Xchange GmbH OX App Suite, a collaborative software suite widely used for email, calendaring, and document management. The vulnerability arises from improper neutralization of input during web page generation, specifically related to the "app loader" functionality. Attackers can craft malicious app references that bypass existing safeguards, allowing injection of malicious script code. This can lead to execution of arbitrary JavaScript in the context of the victim's browser session. The vulnerability is notable because references to apps could contain redirects to unexpected locations, which attackers exploit by forging app references. The vendor has addressed this by enforcing stricter controls on app references to prevent relative references that facilitate the injection. Although no public exploits are currently known, the vulnerability has a CVSS 3.1 score of 5.4, reflecting a medium risk with network attack vector, low attack complexity, requiring low privileges and user interaction, and impacting confidentiality and integrity with a scope change. The vulnerability does not affect availability. The vulnerability was published in February 2024, with the initial reservation in August 2023. Users of OX App Suite should apply the vendor’s patches promptly to mitigate the risk of XSS attacks that could lead to session hijacking, credential theft, or unauthorized actions within the application.

For European organizations, the impact of this vulnerability can be significant, especially for enterprises, educational institutions, and government agencies relying on OX App Suite for daily communication and collaboration. Successful exploitation could allow attackers to execute malicious scripts in users' browsers, potentially leading to theft of sensitive information such as login credentials, session cookies, or personal data. This could further enable lateral movement within the organization’s network or unauthorized access to confidential communications. Given the collaborative nature of OX App Suite, the integrity of shared documents and calendar data could also be compromised. Although availability is not directly impacted, the loss of confidentiality and integrity could disrupt business operations and damage organizational reputation. Additionally, compliance with European data protection regulations such as GDPR could be jeopardized if personal data is exposed or mishandled due to exploitation of this vulnerability.

Organizations should immediately apply the security updates and patches provided by Open-Xchange GmbH to remediate CVE-2023-41708. Beyond patching, administrators should review and tighten input validation and output encoding policies related to app references and URL redirects within their OX App Suite deployments. Implement Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS attacks. Conduct regular security audits and penetration testing focusing on web application input handling. Educate users about the risks of interacting with unexpected links or app references within the suite. Where possible, restrict user privileges to minimize the impact of any successful exploitation. Monitor logs and network traffic for unusual activities that could indicate attempted exploitation. Finally, maintain an incident response plan tailored to web application attacks to quickly contain and remediate any breaches.