CVE-2025-56421: LimeSurvey SQL Injection Vulnerability

CVE-2025-56421 Overview

A SQL Injection vulnerability has been identified in LimeSurvey, an open-source online survey application, affecting versions prior to v.6.15.4+250710. This vulnerability allows a remote attacker to obtain sensitive information from the database by exploiting improper input validation in database queries.

Critical Impact

Remote attackers can extract sensitive survey data, user credentials, and other confidential information stored in the LimeSurvey database without authentication.

Affected Products

• LimeSurvey versions prior to v.6.15.4+250710

Discovery Timeline

• March 10, 2026 - CVE-2025-56421 published to NVD
• March 11, 2026 - Last updated in NVD database

Technical Details for CVE-2025-56421

Vulnerability Analysis

This SQL Injection vulnerability (CWE-89) in LimeSurvey allows unauthenticated remote attackers to manipulate database queries through specially crafted input. The vulnerability is network-accessible and requires no user interaction or prior authentication, making it particularly dangerous for publicly-facing LimeSurvey installations.

The attack targets the confidentiality of data stored in the LimeSurvey database. While the vulnerability does not directly impact system integrity or availability, attackers can leverage successful exploitation to exfiltrate sensitive survey responses, personally identifiable information (PII) collected through surveys, administrator credentials, and internal system configuration details.

Root Cause

The vulnerability stems from improper neutralization of special elements used in SQL commands (CWE-89). User-supplied input is concatenated directly into SQL queries without adequate sanitization or parameterization, allowing attackers to inject malicious SQL statements that are then executed by the database engine.

Attack Vector

The attack vector is network-based, requiring no privileges or user interaction. An attacker can remotely craft malicious HTTP requests containing SQL injection payloads targeting vulnerable endpoints in the LimeSurvey application. The low attack complexity means that standard SQL injection techniques can be employed to extract data from the underlying database.

Typical exploitation involves identifying vulnerable input parameters and injecting SQL payloads designed to enumerate database structure, extract table contents, or bypass authentication mechanisms. Common techniques include UNION-based injection for data extraction and blind SQL injection for scenarios where direct output is not visible.

For detailed technical information about this vulnerability, refer to the GitHub Security Advisory for CVE-2025-56421.

Detection Methods for CVE-2025-56421

Indicators of Compromise

• Unusual database query patterns or errors in application logs indicating malformed SQL statements
• Unexpected database access patterns, particularly bulk data extraction attempts
• HTTP requests containing SQL injection payloads such as single quotes, UNION SELECT statements, or common SQL keywords in unexpected parameters
• Anomalous response sizes or timing patterns that may indicate successful data exfiltration

Detection Strategies

• Deploy Web Application Firewall (WAF) rules configured to detect and block common SQL injection patterns
• Enable detailed logging for database queries and monitor for suspicious query structures
• Implement intrusion detection system (IDS) signatures targeting SQL injection attack patterns
• Review access logs for unusual patterns of requests to LimeSurvey endpoints

Monitoring Recommendations

• Monitor database query logs for evidence of UNION-based, error-based, or time-based blind SQL injection attempts
• Set up alerts for database errors related to SQL syntax that may indicate injection attempts
• Track network traffic to and from the LimeSurvey application server for unusual data transfer volumes
• Implement real-time log analysis to correlate multiple failed injection attempts from the same source

How to Mitigate CVE-2025-56421

Immediate Actions Required

• Upgrade LimeSurvey to version 6.15.4+250710 or later immediately
• If immediate patching is not possible, restrict network access to the LimeSurvey application to trusted IP ranges
• Enable Web Application Firewall protection with SQL injection rule sets
• Review database access logs for evidence of prior exploitation attempts
• Audit database contents for signs of unauthorized data access or extraction

Patch Information

LimeSurvey has addressed this vulnerability in version 6.15.4+250710. Organizations running affected versions should update to this version or later as soon as possible. The official release can be obtained from the LimeSurvey Official Website.

Workarounds

• Implement a Web Application Firewall (WAF) with SQL injection filtering enabled as a temporary mitigation measure
• Restrict access to the LimeSurvey application to trusted networks only using firewall rules or access control lists
• Apply database-level restrictions to limit the privileges of the LimeSurvey database user account
• Consider temporarily taking the survey application offline if it contains highly sensitive data until patching can be completed

# Example: Restrict LimeSurvey access using iptables (temporary mitigation)
# Allow only trusted network range to access web server
iptables -A INPUT -p tcp --dport 80 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP