CVE-2025-3823 is a cross-site scripting (XSS) vulnerability identified in version 1.0 of the SourceCodester Web-based Pharmacy Product Management System. The vulnerability arises from improper input validation and sanitization in the add-stock.php file, specifically involving the parameters txttotalcost, txtproductID, txtprice, and txtexpirydate. An attacker can manipulate these parameters to inject malicious scripts that execute in the context of the victim's browser. This vulnerability is remotely exploitable without requiring authentication or user interaction beyond visiting a crafted URL or interacting with a manipulated input field. The vulnerability is classified as 'problematic' and 'medium' severity by the source, with public disclosure of the exploit details, although no confirmed exploits in the wild have been reported yet. The impact of this XSS flaw includes the potential theft of session cookies, redirection to malicious sites, defacement, or execution of arbitrary JavaScript code, which can lead to further compromise of user accounts or the underlying system. Since the affected product is a pharmacy product management system, exploitation could also undermine the integrity of pharmaceutical inventory data or disrupt business operations. The lack of available patches or mitigations at the time of disclosure increases the urgency for organizations using this system to implement compensating controls.

For European organizations, particularly those in the healthcare and pharmaceutical sectors using the SourceCodester Web-based Pharmacy Product Management System, this vulnerability poses a significant risk. Exploitation could lead to unauthorized access to sensitive business data, manipulation of pharmaceutical stock records, and potential exposure of confidential information related to drug inventories or supplier details. This could disrupt supply chains, cause regulatory compliance issues under GDPR due to data leakage, and damage organizational reputation. Additionally, successful XSS attacks could be leveraged as a foothold for further attacks such as session hijacking or phishing campaigns targeting employees or partners. Given the critical nature of pharmaceutical supply management, even medium-severity vulnerabilities can have outsized operational and financial impacts. The remote exploitability without authentication increases the attack surface, making it easier for threat actors to target multiple organizations across Europe.

1. Immediate implementation of input validation and output encoding: Organizations should sanitize and validate all user-supplied inputs on the server side, especially the parameters txttotalcost, txtproductID, txtprice, and txtexpirydate in add-stock.php. Employ context-aware output encoding to neutralize injected scripts. 2. Deploy Web Application Firewalls (WAFs): Configure WAFs to detect and block common XSS attack patterns targeting the vulnerable parameters. 3. Use Content Security Policy (CSP): Implement strict CSP headers to restrict the execution of unauthorized scripts in the browser context. 4. Monitor and audit logs for suspicious activities related to add-stock.php and associated parameters to detect exploitation attempts early. 5. Isolate the affected system within the network to limit lateral movement if compromised. 6. Engage with the vendor or community to obtain or develop patches or updates addressing this vulnerability. 7. Educate users about phishing and suspicious links, as XSS attacks often rely on social engineering to trigger payloads. 8. Regularly back up critical data to enable recovery in case of data tampering or loss.