CVE-2025-11346 is a vulnerability identified in the ILIAS open-source learning management system affecting versions up to 8.23, 9.13, and 10.1. The root cause is insecure deserialization in the Base64 Decoding Handler component, where the PHP function unserialize is called on manipulated input passed via the f_settings argument. Deserialization vulnerabilities can allow attackers to craft malicious serialized objects that, when unserialized, execute arbitrary code or disrupt application logic. This vulnerability is remotely exploitable without requiring user interaction or elevated privileges, increasing its risk profile. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:L - low privileges), no user interaction (UI:N), and limited impact on confidentiality, integrity, and availability (VC:L, VI:L, VA:L). The vulnerability does not require special conditions such as sandbox escapes or chained exploits, making it straightforward to exploit if an attacker can send crafted requests to the vulnerable component. The recommended mitigation is upgrading to fixed versions 8.24, 9.14, or 10.2, where the deserialization flaw has been addressed. No public exploits or active exploitation campaigns have been reported to date, but the vulnerability's nature and ease of exploitation warrant proactive patching. Organizations relying on ILIAS for e-learning or knowledge management should assess their exposure and apply updates promptly.

For European organizations, especially those in education, government, and public administration that widely use ILIAS, this vulnerability poses a moderate risk. Successful exploitation could lead to remote code execution or denial of service, potentially compromising sensitive educational data, user credentials, or disrupting critical learning services. The impact on confidentiality, integrity, and availability is limited but non-negligible given the role of ILIAS in managing academic records and communications. Disruption or compromise of these systems could affect operational continuity and trust. Since the vulnerability can be exploited remotely without user interaction, attackers could target exposed ILIAS instances over the internet or internal networks. The absence of known exploits in the wild reduces immediate risk but does not eliminate the threat, as attackers may develop exploits post-disclosure. European organizations with outdated ILIAS versions are at higher risk, and failure to patch could lead to targeted attacks or automated scanning and exploitation attempts.

1. Immediately upgrade ILIAS installations to versions 8.24, 9.14, or 10.2, which contain the patch for this deserialization vulnerability. 2. If immediate upgrade is not feasible, implement network-level protections such as web application firewalls (WAFs) to detect and block suspicious payloads targeting the Base64 Decoding Handler component. 3. Restrict access to ILIAS management interfaces and APIs to trusted networks and authenticated users only, minimizing exposure to remote attacks. 4. Monitor application logs for unusual deserialization attempts or malformed Base64-encoded data in requests, which may indicate exploitation attempts. 5. Conduct code reviews and security testing on custom ILIAS plugins or integrations to ensure they do not introduce similar deserialization risks. 6. Educate system administrators and security teams about the risks of insecure deserialization and the importance of timely patching. 7. Employ runtime application self-protection (RASP) tools if available to detect and prevent deserialization attacks dynamically. 8. Regularly backup ILIAS data and configurations to enable recovery in case of compromise or service disruption.