CVE-2019-16173 in LimeSurvey
Summary
by MITRE
LimeSurvey before v3.17.14 allows reflected XSS for escalating privileges from a low-privileged account to, for example, SuperAdmin. This occurs in application/core/Survey_Common_Action.php,
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Analysis
by VulDB Data Team • 08/27/2025
The vulnerability identified as CVE-2019-16173 represents a critical reflected cross-site scripting flaw in LimeSurvey versions prior to 3.17.14. This security weakness resides within the application/core/Survey_Common_Action.php file and enables attackers to escalate privileges from low-privileged user accounts to SuperAdmin level access through maliciously crafted web requests. The flaw demonstrates the classic characteristics of a reflected XSS attack where malicious input is immediately reflected back to the user's browser without proper sanitization or validation, creating a persistent security risk that can be exploited by remote attackers.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding within the Survey_Common_Action.php file. When users interact with LimeSurvey's administrative functions, the application fails to properly sanitize user-supplied parameters before incorporating them into HTTP responses. This allows attackers to inject malicious JavaScript code that executes in the context of other users' browsers, particularly those with elevated privileges. The vulnerability specifically targets the privilege escalation mechanism, enabling attackers to manipulate session tokens, bypass authentication checks, or directly modify administrative permissions through carefully crafted reflected payloads.
The operational impact of this vulnerability extends beyond simple XSS exploitation, as it provides a pathway for attackers to gain unauthorized administrative access to LimeSurvey installations. Once a low-privileged user account is compromised through reflected XSS, attackers can leverage the vulnerability to escalate their privileges to SuperAdmin status, thereby gaining complete control over survey data, user management, system configuration, and potentially accessing sensitive information stored within the LimeSurvey database. This privilege escalation capability significantly amplifies the potential damage and makes the vulnerability particularly attractive to threat actors targeting organizations that rely on LimeSurvey for data collection and management.
Organizations utilizing affected LimeSurvey versions should immediately implement mitigation strategies including applying the vendor-provided security patch to version 3.17.14 or later, which addresses the input validation deficiencies in Survey_Common_Action.php. Network-based mitigations such as web application firewalls can provide additional protection by filtering malicious payloads, though these should not be considered a complete solution. Security teams should also implement comprehensive monitoring of web application logs for suspicious activities and ensure that all user accounts follow principle of least privilege. This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws, and represents a significant concern under the ATT&CK framework's privilege escalation tactics, particularly the use of valid accounts to gain elevated access rights.
The vulnerability demonstrates how seemingly minor input validation issues can create substantial security risks when they occur in administrative pathways. Organizations should conduct thorough security assessments of their web applications to identify similar validation gaps that could enable privilege escalation attacks. Regular security testing including dynamic application security testing and manual penetration testing can help identify such vulnerabilities before they can be exploited by malicious actors. The remediation process should include comprehensive code review of all input handling mechanisms and implementation of robust output encoding practices to prevent similar issues from occurring in other parts of the application.