CVE-2026-3786: Easycms Easycms SQL Injection Vulnerability

CVE-2026-3786 Overview

A SQL injection vulnerability has been discovered in EasyCMS versions up to 1.6. The vulnerability exists in an unknown function within the file /RbacuserAction.class.php, which is part of the Request Parameter Handler component. An attacker can exploit this flaw by manipulating the _order parameter, allowing for SQL injection attacks. This vulnerability can be exploited remotely by authenticated users, and a public exploit has been disclosed. The vendor was contacted regarding this vulnerability but did not respond.

Critical Impact

Authenticated attackers can execute arbitrary SQL queries remotely, potentially leading to unauthorized data access, data manipulation, or complete database compromise.

Affected Products

• EasyCMS versions up to and including 1.6
• Component: /RbacuserAction.class.php (Request Parameter Handler)

Discovery Timeline

• 2026-03-08 - CVE CVE-2026-3786 published to NVD
• 2026-03-09 - Last updated in NVD database

Technical Details for CVE-2026-3786

Vulnerability Analysis

This SQL injection vulnerability (CWE-89) affects the Request Parameter Handler component in EasyCMS. The flaw resides in how the application processes the _order parameter within the RbacuserAction.class.php file. When user-supplied input is passed to this parameter, it is incorporated into SQL queries without proper sanitization or parameterization. This allows an authenticated attacker to inject malicious SQL statements that will be executed by the database engine.

The vulnerability is classified under both CWE-89 (SQL Injection) and CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component), indicating that the root issue stems from inadequate input validation and output encoding practices.

Root Cause

The vulnerability stems from improper input validation in the _order parameter handling logic. The application fails to sanitize or properly escape user-controlled input before incorporating it into SQL queries. This allows special SQL characters and commands to be interpreted as part of the query structure rather than as data values. The absence of prepared statements or parameterized queries exacerbates this issue, enabling direct manipulation of SQL query logic.

Attack Vector

The attack can be executed remotely over the network by authenticated users. An attacker with low-level privileges can craft malicious requests containing SQL injection payloads in the _order parameter. Since the exploit has been publicly disclosed, attackers have access to documented techniques for exploiting this vulnerability.

The vulnerability allows attackers to manipulate SQL query ordering clauses, which can be leveraged to extract sensitive data through time-based or error-based blind SQL injection techniques. Technical details and proof-of-concept information can be found in the GitHub Issue Report and VulDB Advisory.

Detection Methods for CVE-2026-3786

Indicators of Compromise

• Unusual SQL syntax or escape characters appearing in web server access logs, particularly in requests to /RbacuserAction.class.php
• Unexpected database queries containing ORDER BY clauses with suspicious payloads
• Error messages in application logs indicating SQL syntax errors or injection attempts
• Abnormal database query patterns or response times suggesting blind SQL injection probing

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block SQL injection patterns in the _order parameter
• Monitor application logs for requests containing SQL keywords such as UNION, SELECT, INSERT, UPDATE, DELETE, or comment sequences (--, /**/)
• Configure database audit logging to capture and alert on anomalous query patterns
• Deploy intrusion detection systems (IDS) with signatures for SQL injection attack patterns

Monitoring Recommendations

• Enable detailed logging for all requests to the EasyCMS application, particularly those targeting the Request Parameter Handler
• Set up alerts for failed authentication attempts followed by parameter manipulation attempts
• Monitor database server CPU and memory usage for anomalies that may indicate data exfiltration or injection attacks
• Review access logs regularly for requests with abnormally long parameter values or encoded characters

How to Mitigate CVE-2026-3786

Immediate Actions Required

• Restrict network access to EasyCMS installations to trusted IP addresses only until a patch is available
• Implement input validation at the application perimeter using a Web Application Firewall (WAF)
• Review and limit user account privileges to minimize potential impact from exploitation
• Consider temporarily disabling or restricting access to the affected /RbacuserAction.class.php functionality

Patch Information

No official patch information has been released by the vendor. According to the vulnerability report, the vendor was contacted about this disclosure but did not respond. Organizations using EasyCMS should monitor vendor communications and the VulDB Advisory for any future security updates.

Workarounds

• Deploy a Web Application Firewall (WAF) with SQL injection detection rules to filter malicious requests before they reach the application
• If possible, modify the application code to implement prepared statements or parameterized queries for the _order parameter
• Implement strict input validation to allow only expected values (e.g., alphanumeric characters and specific column names) for the _order parameter
• Apply the principle of least privilege to database accounts used by the EasyCMS application to limit potential damage

# Example WAF rule for ModSecurity to block SQL injection in _order parameter
SecRule ARGS:_order "@detectSQLi" \
    "id:100001,\
    phase:2,\
    deny,\
    status:403,\
    log,\
    msg:'SQL Injection attempt detected in _order parameter',\
    tag:'CVE-2026-3786'"