CVE-2025-61168 is a critical vulnerability identified in the cms_rest.php component of SIGB PMB version 8.0.1.14, a popular integrated library system used primarily in academic and public libraries. The flaw stems from unsafe deserialization practices (CWE-502), where the application unserializes data from an arbitrary file without proper validation or sanitization. This allows a remote attacker to craft malicious serialized payloads that, when processed by the vulnerable component, lead to arbitrary code execution on the server. The vulnerability is remotely exploitable over the network (AV:N), requires no privileges (PR:N), no user interaction (UI:N), and affects the confidentiality, integrity, and availability of the system (C:H/I:H/A:H). The CVSS 3.1 base score of 9.8 reflects the critical nature of this flaw. Although no public exploits have been reported yet, the vulnerability's characteristics suggest it could be weaponized quickly. The lack of available patches at the time of disclosure increases the urgency for organizations to implement temporary mitigations and monitor for suspicious activity. This vulnerability could allow attackers to gain full control over affected systems, potentially leading to data breaches, service disruption, or lateral movement within networks.

For European organizations, the impact of CVE-2025-61168 is substantial. SIGB PMB is widely used in European academic, public, and research libraries, making these institutions prime targets. Successful exploitation could lead to full system compromise, exposing sensitive patron data, internal documents, and intellectual property. The integrity of library catalogs and digital resources could be undermined, disrupting access to critical information services. Availability could also be affected, causing denial of service or ransomware deployment. Given the criticality and ease of exploitation, attackers could leverage this vulnerability for espionage, data theft, or sabotage, particularly targeting institutions involved in research, education, and cultural preservation. The reputational damage and regulatory consequences under GDPR for data breaches could be severe. Furthermore, compromised systems could serve as footholds for broader attacks against connected networks within universities or government entities.

Immediate mitigation steps include restricting network access to the cms_rest.php endpoint by implementing firewall rules or network segmentation to limit exposure to trusted internal IPs only. Organizations should monitor logs for unusual unserialization attempts or unexpected file accesses related to the vulnerable component. Deploying web application firewalls (WAFs) with custom rules to detect and block malicious serialized payloads can provide temporary protection. Until an official patch is released, consider disabling or removing the cms_rest.php component if feasible. Conduct thorough audits of SIGB PMB installations to identify all instances and versions in use. Educate system administrators about the risks of unsafe deserialization and enforce strict input validation and sanitization in custom integrations. Once a patch becomes available, prioritize its deployment across all affected systems. Additionally, implement endpoint detection and response (EDR) solutions to detect post-exploitation activities and maintain regular backups to enable recovery from potential attacks.