CVE-2025-34031 is a path traversal vulnerability identified in the Moodle Learning Management System's Jmol plugin, specifically affecting version 6.1 and prior. The vulnerability arises from improper input validation in the jsmol.php script, where a query parameter is directly passed to the PHP function file_get_contents() without sanitization or restriction. This flaw allows an attacker to craft a malicious query string that traverses directories on the server's filesystem, enabling the reading of arbitrary files. Since the vulnerability does not require authentication or user interaction, it can be exploited remotely by any attacker with network access to the Moodle instance. The exposure of sensitive files, including configuration files and database credentials, can lead to further compromise of the system and data breaches. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N) reflects a high-severity rating of 8.7, emphasizing the ease of exploitation and the significant confidentiality impact. The Shadowserver Foundation observed exploitation attempts in October 2025, confirming active interest by threat actors. No patches or official fixes have been released at the time of this report, increasing the urgency for mitigation. The vulnerability is classified under CWE-22, which pertains to improper limitation of pathname to a restricted directory, a common and critical web application security issue. Given Moodle's widespread use in educational institutions worldwide, the vulnerability poses a substantial risk to the confidentiality and integrity of educational data and infrastructure.

For European organizations, especially educational institutions, universities, and research centers that widely deploy Moodle LMS, this vulnerability presents a significant risk. Exploitation can lead to unauthorized disclosure of sensitive information such as database credentials, user data, and internal configuration files, potentially enabling further attacks like privilege escalation or data exfiltration. The breach of confidential academic records and personal data could result in regulatory penalties under GDPR, reputational damage, and operational disruptions. Since Moodle is often integrated with other academic and administrative systems, the compromise could cascade, affecting broader organizational IT infrastructure. The lack of authentication requirement and ease of exploitation increase the likelihood of attacks, potentially targeting high-profile European institutions. Additionally, the exposure of configuration files may allow attackers to pivot within networks or launch ransomware or espionage campaigns. The impact on availability is limited but confidentiality and integrity are severely affected.

Given the absence of an official patch, European organizations should immediately implement compensating controls. First, restrict access to the vulnerable jsmol.php endpoint using web application firewalls (WAFs) or access control lists (ACLs) to limit requests to trusted IP ranges or authenticated users only. Implement strict input validation and sanitization at the web server or application proxy level to block path traversal patterns such as '../'. Monitor web server logs for suspicious query parameters indicative of traversal attempts. Consider disabling or removing the Jmol plugin if it is not essential to reduce the attack surface. Conduct thorough audits of Moodle installations to identify vulnerable versions and isolate affected systems. Prepare for rapid patch deployment once an official fix is released by Moodle. Additionally, enforce least privilege principles on file system permissions to minimize the impact of file disclosure. Educate system administrators about this vulnerability and encourage immediate incident response readiness. Regular backups and network segmentation can help contain potential breaches.