CVE-2026-5148: YunaiV yudao-cloud SQL Injection Vulnerability

CVE-2026-5148 Overview

A SQL injection vulnerability has been identified in YunaiV yudao-cloud up to version 2026.01. This vulnerability affects the /admin-api/system/mail-log/page endpoint, where improper handling of the toMail parameter allows attackers to inject malicious SQL commands. The attack can be initiated remotely by authenticated users with administrative privileges, potentially leading to unauthorized data access, modification, or system compromise.

Critical Impact

Authenticated attackers can exploit this SQL injection vulnerability to extract sensitive data from the database, modify records, or potentially escalate their access within the yudao-cloud application.

Affected Products

• YunaiV yudao-cloud version 2026.01 and earlier
• Systems utilizing the /admin-api/system/mail-log/page endpoint

Discovery Timeline

• 2026-03-30 - CVE-2026-5148 published to NVD
• 2026-04-01 - Last updated in NVD database

Technical Details for CVE-2026-5148

Vulnerability Analysis

This vulnerability represents a classic SQL injection flaw (CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component) in the yudao-cloud administrative interface. The vulnerable endpoint /admin-api/system/mail-log/page processes the toMail parameter without proper input sanitization or parameterized queries, allowing attackers to manipulate database queries directly.

The attack requires network access and elevated privileges within the application (administrative access), but once those conditions are met, the exploitation complexity is low. Successful exploitation could result in confidentiality, integrity, and availability impacts to the underlying database system.

The vendor was contacted early about this disclosure but did not respond, leaving systems potentially exposed without an official patch.

Root Cause

The root cause of this vulnerability lies in the failure to properly sanitize or parameterize user-controlled input in the toMail argument before incorporating it into SQL queries. The application appears to construct database queries by directly concatenating user input rather than using prepared statements or parameterized queries, which is a fundamental secure coding violation.

Attack Vector

The attack vector is network-based, targeting the administrative API endpoint. An attacker with valid administrative credentials can craft malicious requests to the /admin-api/system/mail-log/page endpoint, embedding SQL syntax within the toMail parameter. The injected SQL commands are then executed against the backend database with the privileges of the application's database user.

The vulnerability mechanism involves sending specially crafted HTTP requests to the affected endpoint where the toMail parameter accepts arbitrary input that gets incorporated into SQL queries without proper sanitization. Attackers can leverage standard SQL injection techniques such as UNION-based injection, error-based injection, or blind injection to extract database contents, modify data, or potentially execute stored procedures. For detailed technical analysis, refer to the GitHub Vulnerability Note.

Detection Methods for CVE-2026-5148

Indicators of Compromise

• Unusual or malformed requests to /admin-api/system/mail-log/page containing SQL syntax characters such as single quotes, semicolons, or SQL keywords in the toMail parameter
• Database error messages appearing in application logs related to mail log queries
• Unexpected database queries or execution patterns originating from the yudao-cloud application
• Anomalous data access patterns to sensitive tables from admin API sessions

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect SQL injection patterns in requests to the /admin-api/system/mail-log/page endpoint
• Deploy database activity monitoring to identify suspicious query patterns or unauthorized data extraction
• Enable detailed logging for the admin API endpoints and monitor for requests containing SQL injection indicators
• Use intrusion detection systems (IDS) configured with SQL injection signatures targeting this specific endpoint

Monitoring Recommendations

• Monitor HTTP request logs for the toMail parameter containing special characters (`, ', ", --, ;, UNION, SELECT, etc.)
• Set up alerts for database errors or exceptions originating from mail log functionality
• Track administrative user sessions for unusual activity patterns or bulk data access
• Correlate network traffic with database query logs to identify potential exploitation attempts

How to Mitigate CVE-2026-5148

Immediate Actions Required

• Restrict network access to the /admin-api/system/mail-log/page endpoint using firewall rules or reverse proxy configurations
• Implement additional authentication controls and audit logging for administrative API endpoints
• Deploy a Web Application Firewall (WAF) with SQL injection protection rules enabled
• Review and restrict administrative privileges to minimize the attack surface

Patch Information

At the time of publication, the vendor (YunaiV) has not responded to disclosure attempts or provided an official patch. Organizations using yudao-cloud should monitor the VulDB Vulnerability Entry and official vendor channels for updates. Consider contacting the vendor directly for remediation guidance.

Workarounds

• Implement input validation and sanitization at the application gateway or WAF level to filter SQL injection patterns from the toMail parameter
• Consider disabling or restricting access to the vulnerable mail log pagination feature until a patch is available
• Use network segmentation to limit access to administrative interfaces from trusted networks only
• Deploy virtual patching through a WAF to block exploitation attempts while awaiting an official fix

Organizations are encouraged to review the GitHub Admin API Log Analysis for additional technical context and the VulDB CTI entry for threat intelligence updates.