CVE-2026-26745: OpenSourcePOS SQL Injection Vulnerability

CVE-2026-26745 Overview

OpenSourcePOS 3.4.1 contains a second order SQL Injection vulnerability in the handling of the currency_symbol configuration field. Although the input is initially stored without immediate execution, it is later concatenated into a dynamically constructed SQL query without proper sanitization or parameter binding. This allows an attacker with access to modify the currency_symbol value to inject arbitrary SQL expressions, which are executed when the affected query is subsequently processed.

Critical Impact

Authenticated attackers can exploit the second order SQL injection to extract sensitive data from the database, potentially exposing customer information, financial records, and other confidential business data stored in the point-of-sale system.

Affected Products

• OpenSourcePOS Open Source Point of Sale version 3.4.1

Discovery Timeline

• 2026-02-20 - CVE CVE-2026-26745 published to NVD
• 2026-02-24 - Last updated in NVD database

Technical Details for CVE-2026-26745

Vulnerability Analysis

This vulnerability is classified as CWE-89 (SQL Injection) and specifically manifests as a second order SQL injection. Unlike traditional SQL injection where malicious input is immediately executed, second order SQL injection involves storing the payload first and then triggering its execution during a subsequent database operation. In this case, the currency_symbol configuration field accepts user input that is stored in the database without immediate harm. However, when the application later retrieves this value and concatenates it directly into a SQL query without proper sanitization or parameterized queries, the injected SQL expressions are executed.

The attack requires network access and low privilege authentication to modify the currency symbol configuration. The complexity is elevated because the attacker must understand the application's data flow and identify when the stored payload will be triggered. Successful exploitation can lead to unauthorized access to confidential information stored in the database.

Root Cause

The root cause of this vulnerability lies in improper input handling within the OpenSourcePOS application. The currency_symbol configuration field lacks adequate input validation and output encoding. While the application may store the user-provided value without issues, the subsequent use of this value in dynamically constructed SQL queries without parameterized statements or proper escaping creates the injection point. This architectural flaw allows stored malicious payloads to execute when the affected query processes the tainted configuration value.

Attack Vector

The attack vector is network-based, requiring an authenticated user with permissions to modify system configuration settings. An attacker would first navigate to the currency configuration section and input a maliciously crafted SQL payload as the currency symbol value. This payload is stored in the database. Later, when the application executes a query that incorporates the currency symbol value through string concatenation, the injected SQL commands are executed against the database. This could enable data exfiltration, enumeration of database structure, or other unauthorized database operations.

The vulnerability mechanism involves the application retrieving the stored currency symbol and directly embedding it into SQL statements. Without prepared statements or parameterized queries, the database interprets the injected content as executable SQL code rather than literal data. For detailed technical analysis, refer to the CVE research documentation.

Detection Methods for CVE-2026-26745

Indicators of Compromise

• Unusual or malformed values in the currency_symbol configuration field containing SQL syntax such as single quotes, UNION statements, or comment operators
• Database error logs showing syntax errors or unexpected query behavior related to currency display functions
• Audit logs indicating multiple modifications to currency configuration settings by the same user
• Evidence of data exfiltration or unauthorized database queries in database activity logs

Detection Strategies

• Implement database activity monitoring to detect anomalous queries originating from currency-related application functions
• Deploy web application firewall (WAF) rules to identify SQL injection patterns in configuration field submissions
• Enable application-level logging for all configuration changes and review for suspicious input patterns
• Utilize SentinelOne Singularity Platform to detect post-exploitation behaviors and lateral movement following successful SQL injection

Monitoring Recommendations

• Monitor database query logs for queries containing unexpected SQL syntax in currency symbol positions
• Set up alerts for configuration changes to the currency_symbol field, especially those containing special characters
• Track user session activity for accounts that have modified currency settings followed by unusual database access patterns
• Review application error logs for SQL syntax errors that may indicate injection attempts

How to Mitigate CVE-2026-26745

Immediate Actions Required

• Audit the current currency_symbol configuration value for any malicious SQL content and sanitize if necessary
• Restrict access to configuration modification features to only essential administrative accounts
• Implement input validation on the currency_symbol field to allow only expected currency symbol characters
• Consider temporarily disabling the currency symbol customization feature until a patch is applied

Patch Information

At the time of publication, users should monitor the OpenSourcePOS GitHub repository for security updates addressing this vulnerability. Review the CVE research documentation for additional technical details and mitigation guidance. Upgrade to the latest version of OpenSourcePOS when a patched release becomes available.

Workarounds

• Implement strict input validation on the server side to allow only whitelisted characters for currency symbols (letters, common currency glyphs, numbers)
• Modify the application code to use prepared statements with parameter binding when retrieving and using the currency symbol value in queries
• Apply principle of least privilege by restricting database user permissions for the OpenSourcePOS application
• Consider using a web application firewall to filter SQL injection attempts targeting configuration endpoints

The recommended approach is to ensure all database queries that incorporate user-controllable configuration values use parameterized queries or prepared statements. Input validation should be implemented as a defense-in-depth measure, restricting the currency symbol field to legitimate currency characters only.