CVE-2014-2571 in Moodle
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the quiz_question_tostring function in mod/quiz/editlib.php in Moodle through 2.3.11, 2.4.x before 2.4.9, 2.5.x before 2.5.5, and 2.6.x before 2.6.2 allows remote authenticated users to inject arbitrary web script or HTML via a quiz question.
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Analysis
by VulDB Data Team • 05/08/2026
The CVE-2014-2571 vulnerability represents a critical cross-site scripting flaw within the Moodle learning management system that affects multiple version branches including 2.3.11, 2.4.x through 2.4.8, 2.5.x through 2.5.4, and 2.6.x through 2.6.1. This vulnerability resides in the quiz_question_tostring function located in the mod/quiz/editlib.php file, which is a core component responsible for rendering quiz questions within the Moodle platform. The flaw allows authenticated users to execute malicious scripts through the quiz question interface, creating a significant security risk for educational institutions that rely on Moodle for their online learning environments.
The technical nature of this vulnerability stems from inadequate input sanitization within the quiz_question_tostring function, which processes and displays quiz question data without proper HTML escaping or validation. When authenticated users create or modify quiz questions, the system fails to properly sanitize user-supplied content before rendering it in the web interface. This allows attackers to inject malicious JavaScript code, HTML tags, or other harmful content that gets executed in the context of other users' browsers when they view the quiz questions. The vulnerability specifically targets the quiz module functionality, making it particularly dangerous in educational settings where teachers and students frequently interact with quiz content.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform various malicious activities including session hijacking, data exfiltration, and unauthorized access to user accounts. In a typical educational environment, this could allow an attacker with access to the quiz module to steal student information, manipulate quiz results, or gain persistent access to the platform through stolen session cookies. The vulnerability affects authenticated users, meaning that any individual with legitimate access to the Moodle system could potentially exploit this flaw, making it particularly concerning for institutions with large user bases where user access management might be less stringent.
Security professionals should note that this vulnerability aligns with CWE-79, which describes cross-site scripting flaws in web applications, and can be mapped to ATT&CK technique T1566.001 for initial access through malicious web content. The remediation strategy involves applying the official patches released by Moodle for the affected versions, which typically include proper input sanitization and HTML escaping mechanisms in the quiz_question_tostring function. Organizations should prioritize upgrading to patched versions of Moodle and implement additional monitoring for suspicious quiz question content. The vulnerability demonstrates the importance of proper input validation in web applications and highlights the need for regular security updates in educational technology platforms where user-generated content processing is common.
The broader implications of this vulnerability underscore the critical importance of maintaining up-to-date security practices in educational technology environments. Institutions relying on Moodle or similar learning management systems must establish robust patch management processes and security monitoring procedures to prevent exploitation of similar vulnerabilities. The ease of exploitation through authenticated access points makes this type of vulnerability particularly dangerous in environments where multiple users have access to content creation features, as it can serve as a foothold for more extensive attacks against the entire educational platform.