CVE-2024-23189 is a cross-site scripting (XSS) vulnerability identified in the OX App Suite, a collaborative software product by Open-Xchange GmbH. The vulnerability stems from improper sanitization of user-generated content, specifically embedded content references within task items. This flaw allows an attacker to inject and execute arbitrary script code in the context of a victim's browser session when viewing or interacting with affected tasks. Successful exploitation requires the attacker to have temporary access to the victim's account, access to another account within the same organizational context, or to trick users via social engineering into importing malicious external content. Once exploited, attackers can perform unauthorized API calls on behalf of the user or extract sensitive information from the user's account, potentially leading to data leakage or further compromise. The CVSS v3.1 base score is 5.4 (medium), reflecting that the attack vector is network-based with low attack complexity, no privileges required, but user interaction is necessary. The impact affects confidentiality and integrity but not availability. Open-Xchange has addressed the issue by enhancing input sanitization and released patches to remediate the vulnerability. No known public exploits exist at this time, but the risk remains significant for environments where OX App Suite is deployed and users handle embedded content in tasks.

For European organizations using OX App Suite, this vulnerability poses a risk of unauthorized data access and manipulation within user accounts. Attackers exploiting this flaw could extract sensitive corporate or personal information, potentially leading to data breaches or compliance violations under regulations like GDPR. The ability to perform malicious API requests could allow attackers to escalate their access or disrupt workflows. Since exploitation requires user interaction or temporary account access, insider threats or phishing campaigns could be leveraged to trigger attacks. Organizations relying on OX App Suite for email, calendaring, and collaboration may face confidentiality and integrity risks, impacting business operations and trust. The medium severity indicates a moderate but actionable threat, especially in sectors with sensitive data such as finance, healthcare, or government within Europe.

European organizations should immediately apply the official patches and updates released by Open-Xchange GmbH to remediate CVE-2024-23189. Beyond patching, administrators should enforce strict access controls and monitor for unusual account activities that could indicate temporary unauthorized access. Implement multi-factor authentication (MFA) to reduce the risk of account compromise. Educate users about the risks of importing external content and train them to recognize social engineering attempts. Review and restrict the use of embedded content in tasks where possible. Employ web application firewalls (WAFs) with custom rules to detect and block suspicious script injections targeting OX App Suite. Regularly audit API usage logs for anomalies that could signal exploitation attempts. Finally, maintain an incident response plan tailored to web application vulnerabilities to quickly contain and remediate any detected exploitation.