CVE-2026-30576: Pharmacy Product Management System Flaw

CVE-2026-30576 Overview

A Business Logic vulnerability exists in SourceCodester Pharmacy Product Management System 1.0 in the add-stock.php file. The application fails to validate the txtprice and txttotalcost parameters during stock entry, allowing negative financial values to be submitted. This leads to corruption of financial records, allowing attackers to manipulate inventory asset values and procurement costs.

Critical Impact

Attackers can manipulate financial records by submitting negative price and cost values during stock entry, potentially corrupting inventory asset valuations and procurement cost calculations across the pharmacy management system.

Affected Products

• Senior-walter Web-based Pharmacy Product Management System 1.0
• SourceCodester Pharmacy Product Management System (add-stock.php component)

Discovery Timeline

• 2026-03-27 - CVE CVE-2026-30576 published to NVD
• 2026-03-31 - Last updated in NVD database

Technical Details for CVE-2026-30576

Vulnerability Analysis

This vulnerability represents a classic business logic flaw stemming from inadequate input validation (CWE-20). The add-stock.php file in the Pharmacy Product Management System processes stock entry requests without verifying that financial values submitted through the txtprice and txttotalcost parameters are logically valid (i.e., positive numbers).

By accepting negative values for these critical financial fields, the application allows attackers to corrupt the integrity of financial records. This can result in artificially deflated inventory valuations, incorrect procurement cost calculations, and ultimately unreliable financial reporting for the pharmacy business.

Root Cause

The root cause is improper input validation in the stock entry functionality. The application does not enforce business rules requiring that price and total cost values be non-negative. This oversight allows any authenticated user with stock entry privileges to submit logically invalid financial data that the system processes without question.

The vulnerable component accepts user-supplied values directly from HTTP request parameters without server-side validation constraints, relying potentially only on client-side controls that can be easily bypassed.

Attack Vector

The attack is network-based and requires no user interaction. An attacker can exploit this vulnerability by intercepting or crafting HTTP requests to the add-stock.php endpoint with negative values for the txtprice and txttotalcost parameters.

The exploitation process involves:

1. Accessing the stock entry form in the pharmacy management system
2. Submitting a stock entry with negative values for price or total cost fields
3. The application processes these values without validation
4. Financial records become corrupted with invalid data

For technical details and proof-of-concept information, refer to the GitHub PoC for Pharmacy System.

Detection Methods for CVE-2026-30576

Indicators of Compromise

• Database records containing negative values in price or cost fields for stock entries
• Abnormal inventory valuations showing negative total asset values
• Discrepancies between physical inventory counts and system-reported financial values
• Unusual patterns in the add-stock.php access logs showing repeated submissions

Detection Strategies

• Implement database monitoring to alert on INSERT or UPDATE operations with negative values in financial columns
• Deploy web application firewall (WAF) rules to detect and block HTTP requests containing negative numeric values in price-related parameters
• Review application logs for requests to add-stock.php with anomalous parameter values
• Establish database integrity checks that run periodically to identify logically invalid financial records

Monitoring Recommendations

• Enable detailed logging for all stock entry transactions including submitted parameter values
• Configure real-time alerts for database triggers that detect negative financial values being inserted
• Implement financial reconciliation reports that flag inventory records with suspicious values
• Monitor for bulk modification attempts that could indicate automated exploitation

How to Mitigate CVE-2026-30576

Immediate Actions Required

• Implement server-side input validation to reject negative values for txtprice and txttotalcost parameters
• Audit existing database records for negative financial values and correct any corrupted entries
• Consider implementing role-based access controls to limit who can perform stock entry operations
• Deploy WAF rules as a temporary mitigation while awaiting a vendor patch

Patch Information

No official vendor patch is currently available for this vulnerability. Organizations using the affected Senior-walter Web-based Pharmacy Product Management System 1.0 should implement the workarounds described below and monitor for vendor updates.

Workarounds

• Add server-side validation in add-stock.php to ensure txtprice and txttotalcost accept only positive numeric values
• Implement database constraints (CHECK constraints) on financial columns to prevent negative values at the database level
• Deploy input validation at the WAF level to reject requests with negative values in financial parameters
• Consider isolating the application from untrusted networks until a proper fix can be implemented

# Example MySQL constraint to prevent negative values
ALTER TABLE stock_entries 
ADD CONSTRAINT chk_price_positive CHECK (txtprice >= 0),
ADD CONSTRAINT chk_totalcost_positive CHECK (txttotalcost >= 0);