CVE-2026-1123: Yonyou KSOA SQL Injection Vulnerability

CVE-2026-1123 Overview

A SQL Injection vulnerability was identified in Yonyou KSOA 9.0 affecting the /worksheet/work_mod.jsp file within the HTTP GET Parameter Handler component. The vulnerability allows attackers to manipulate the ID argument parameter to inject malicious SQL code. This attack can be launched remotely without authentication, and the exploit has been publicly disclosed. The vendor was contacted about this disclosure but did not respond.

Critical Impact

Remote attackers can exploit this SQL Injection vulnerability to manipulate database queries, potentially leading to unauthorized data access, data modification, or data exfiltration from the affected Yonyou KSOA system.

Affected Products

• Yonyou KSOA 9.0
• HTTP GET Parameter Handler component in /worksheet/work_mod.jsp

Discovery Timeline

• 2026-01-18 - CVE-2026-1123 published to NVD
• 2026-01-18 - Last updated in NVD database

Technical Details for CVE-2026-1123

Vulnerability Analysis

This vulnerability is classified as CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component - Injection). The affected component fails to properly sanitize user-supplied input in the ID parameter before incorporating it into SQL queries. When a user sends an HTTP GET request to /worksheet/work_mod.jsp, the application directly processes the ID parameter value without adequate validation or parameterization.

The network-accessible nature of this vulnerability means that any remote attacker with network access to the KSOA application can attempt exploitation without requiring authentication or user interaction. Successful exploitation could allow attackers to read, modify, or delete data from the underlying database, depending on the database user privileges and the specific SQL injection context.

Root Cause

The root cause of this vulnerability is improper input validation and lack of parameterized queries in the work_mod.jsp file. The application directly concatenates user-supplied input from the ID GET parameter into SQL statements, enabling injection attacks. This represents a fundamental failure to follow secure coding practices for database interactions.

Attack Vector

The attack vector is network-based, requiring no privileges or user interaction. An attacker can craft malicious HTTP GET requests to the /worksheet/work_mod.jsp endpoint with specially crafted ID parameter values containing SQL injection payloads. The injected SQL code is then executed by the database server with the privileges of the application's database connection.

The vulnerability can be exploited through standard SQL injection techniques such as UNION-based injection, error-based injection, or blind SQL injection, depending on the application's error handling and response behavior. For technical details and proof-of-concept information, refer to the GitHub CVE Issue Discussion.

Detection Methods for CVE-2026-1123

Indicators of Compromise

• Unusual HTTP GET requests to /worksheet/work_mod.jsp containing SQL syntax in the ID parameter
• Database error messages appearing in web application logs related to malformed SQL queries
• Unexpected database queries or data access patterns in database audit logs
• Web server access logs showing requests with encoded SQL injection payloads targeting the vulnerable endpoint

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block SQL injection patterns in HTTP GET parameters
• Monitor application logs for SQL syntax errors or database connection anomalies
• Deploy intrusion detection systems (IDS) with signatures for common SQL injection attack patterns
• Review database query logs for suspicious SELECT, UNION, or other SQL commands originating from the web application

Monitoring Recommendations

• Enable detailed logging for all requests to /worksheet/work_mod.jsp
• Configure database audit logging to capture all queries executed by the KSOA application user
• Set up alerting for unusual data access patterns or bulk data retrieval operations
• Monitor network traffic for encoded payloads targeting the vulnerable endpoint

How to Mitigate CVE-2026-1123

Immediate Actions Required

• Restrict network access to the Yonyou KSOA 9.0 application to trusted IP addresses only
• Implement Web Application Firewall (WAF) rules to filter SQL injection attempts in the ID parameter
• Consider disabling or restricting access to /worksheet/work_mod.jsp if not business-critical
• Review database user privileges and apply principle of least privilege to the KSOA application database account

Patch Information

No official patch information is available from the vendor. According to the vulnerability disclosure, the vendor was contacted about this issue but did not respond. Organizations should implement compensating controls and monitor for any future security updates from Yonyou. Additional technical details are available at VulDB #341715.

Workarounds

• Deploy a Web Application Firewall with SQL injection detection rules in front of the KSOA application
• Implement input validation at the network perimeter to sanitize the ID parameter
• Restrict access to the vulnerable JSP endpoint using network segmentation or access control lists
• Consider implementing a reverse proxy with request filtering capabilities to block malicious requests

# Example WAF rule concept for ModSecurity
# Block SQL injection patterns in ID parameter
SecRule ARGS:ID "@detectSQLi" \
    "id:1001,\
    phase:2,\
    deny,\
    status:403,\
    log,\
    msg:'SQL Injection attempt detected in ID parameter',\
    tag:'CVE-2026-1123'"