CVE-2025-56605 identifies a reflected Cross-Site Scripting (XSS) vulnerability in the PuneethReddyHC Event Management System version 1.0, specifically within the register.php backend script. The vulnerability stems from improper validation and sanitization of the 'mobile' parameter sent via POST requests. When this parameter is echoed back in the HTTP response without adequate sanitization, it enables an attacker to inject malicious JavaScript code. This code executes in the context of the victim's browser, potentially allowing session hijacking, credential theft, or other malicious actions depending on the victim's privileges and browser environment. The reflected nature of this XSS means the malicious script is not stored on the server but delivered via crafted requests, requiring user interaction such as clicking a malicious link or submitting a manipulated form. The CVSS 3.1 score of 5.4 reflects a medium severity, with network attack vector, low attack complexity, no privileges required, but requiring user interaction. The impact affects confidentiality and integrity to a limited extent but does not affect availability. No patches or known exploits are currently available, indicating the vulnerability is newly disclosed. The weakness aligns with CWE-79, a common web application security flaw. Mitigation involves proper input validation, output encoding, and potentially implementing Content Security Policy (CSP) headers to reduce the risk of script execution.

The primary impact of this vulnerability is the potential execution of arbitrary JavaScript code in the browsers of users interacting with the vulnerable event management system. This can lead to theft of session cookies, user credentials, or other sensitive information accessible via the browser context. It may also enable attackers to perform actions on behalf of the victim if the victim is authenticated, leading to unauthorized operations within the application. While the vulnerability does not directly affect system availability, it compromises confidentiality and integrity of user data. For organizations, this could result in data breaches, loss of user trust, and potential regulatory penalties if personal data is exposed. Since the vulnerability requires user interaction, the risk is somewhat mitigated but remains significant, especially in environments where users may be targeted via phishing or social engineering. The lack of patches means organizations must rely on compensating controls until an official fix is released.

Organizations using PuneethReddyHC Event Management System 1.0 should immediately implement strict input validation on the 'mobile' parameter, ensuring that only expected data formats (e.g., numeric digits) are accepted. Employ output encoding techniques such as HTML entity encoding before reflecting any user input back in HTTP responses to prevent script execution. Implement Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in the browser. Additionally, consider deploying Web Application Firewalls (WAFs) with rules to detect and block common XSS attack patterns targeting this parameter. Educate users about the risks of clicking untrusted links or submitting data from unknown sources. Monitor application logs for suspicious input patterns and anomalous user behavior. Finally, coordinate with the software vendor or development team to obtain or develop a patch that properly sanitizes inputs at the server side and update the system promptly once available.