CVE-2025-11345 is a deserialization vulnerability found in the ILIAS learning management system versions up to 8.23, 9.13, and 10.1. The vulnerability resides in the Test Import component's unserialize function, which improperly handles serialized data input. Deserialization flaws occur when untrusted data is converted back into objects without sufficient validation, potentially allowing attackers to craft malicious payloads that execute arbitrary code, manipulate application logic, or cause denial of service. This vulnerability can be triggered remotely without authentication, although it requires some user interaction, such as triggering the import functionality with crafted data. The CVSS 4.0 score of 5.1 reflects a medium severity, considering the network attack vector, low complexity, no privileges required, but user interaction needed, and limited impact on confidentiality, integrity, and availability. The flaw does not require system component compromise or privilege escalation to exploit but can lead to significant security issues if leveraged. The recommended mitigation is upgrading ILIAS to versions 8.24, 9.14, or 10.2, where the vulnerability has been patched. No public exploits or active exploitation campaigns have been reported, but the vulnerability's nature makes it a potential target for attackers aiming at educational institutions or organizations relying on ILIAS for e-learning and testing.

For European organizations, especially educational institutions and government bodies using ILIAS, this vulnerability poses a risk of unauthorized code execution, data manipulation, or service disruption. Confidentiality could be compromised if attackers gain access to sensitive educational data or user credentials. Integrity risks include tampering with test results or course content, undermining trust in the platform. Availability impacts could arise from denial-of-service conditions caused by malformed serialized data. Given ILIAS's widespread use in countries like Germany, Austria, and Switzerland, exploitation could disrupt critical educational services and affect large user bases. The medium severity indicates that while the risk is not critical, successful exploitation could have meaningful operational and reputational consequences. Organizations with limited patch management capabilities or those running outdated versions are particularly vulnerable. The lack of known exploits reduces immediate threat but does not eliminate future risks, especially as attackers often target educational platforms for espionage or disruption.

Organizations should immediately upgrade affected ILIAS installations to versions 8.24, 9.14, or 10.2 to remediate the vulnerability. In addition, administrators should audit and restrict access to the Test Import functionality to trusted users only, minimizing exposure. Implement network-level protections such as web application firewalls (WAFs) with custom rules to detect and block suspicious serialized payloads targeting the import feature. Conduct thorough input validation and sanitization on all serialized data inputs where possible. Regularly monitor logs for unusual activity related to deserialization or import operations. Educate users about the risks of interacting with untrusted data and ensure that backups are maintained to recover from potential attacks. Finally, maintain an up-to-date inventory of ILIAS instances and versions deployed across the organization to ensure timely patching and vulnerability management.