CVE-2025-11346 is a deserialization vulnerability identified in the ILIAS e-learning platform, affecting versions up to 8.23, 9.13, and 10.1. The vulnerability stems from unsafe handling of the f_settings parameter within the Base64 Decoding Handler component, which uses PHP's unserialize function without adequate input validation or sanitization. This flaw allows remote attackers to craft malicious serialized data that, when deserialized, can manipulate application logic or execute arbitrary code depending on the context and available classes. The attack vector is network-based, requiring no authentication or user interaction, which increases the risk of exploitation. The CVSS 4.0 score is 5.3 (medium), reflecting moderate impact on confidentiality, integrity, and availability, with low complexity and no privileges required. Although no exploits are currently known in the wild, the vulnerability poses a significant risk due to the critical role of ILIAS in managing sensitive educational data and user information. The recommended remediation is upgrading to patched versions 8.24, 9.14, or 10.2, which address the unsafe deserialization by improving input handling and validation in the affected component.

For European organizations, particularly universities, schools, and public institutions relying on ILIAS for e-learning and content management, this vulnerability could lead to unauthorized data access, data tampering, or service disruption. Attackers exploiting this flaw could potentially execute arbitrary code or manipulate serialized objects to escalate privileges or bypass security controls. This threatens the confidentiality of student and staff data, the integrity of educational content, and the availability of learning services. Given the remote and unauthenticated nature of the exploit, widespread automated attacks could target vulnerable installations, causing operational disruptions and reputational damage. The impact is heightened in Europe due to strict data protection regulations (e.g., GDPR), where breaches could result in significant legal and financial penalties.

Organizations should immediately upgrade ILIAS installations to versions 8.24, 9.14, or 10.2 or later, which contain fixes for this vulnerability. In parallel, administrators should audit and restrict network access to the ILIAS application, employing web application firewalls (WAFs) to detect and block suspicious serialized payloads. Implementing strict input validation and disabling unsafe PHP functions like unserialize where possible can reduce risk. Monitoring logs for unusual deserialization attempts and anomalous application behavior is critical for early detection. Additionally, organizations should conduct security assessments of their ILIAS deployments and ensure regular patch management processes are in place. Where upgrading is not immediately feasible, consider isolating the affected components and limiting exposure to untrusted networks.