CVE-2025-49947 is a reflected Cross-site Scripting (XSS) vulnerability identified in the WooCommerce Registration Fields Plugin - Custom Signup Fields developed by extendons, affecting all versions up to and including 3.2.3. This vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, which allows an attacker to inject malicious JavaScript code into web responses. When a victim interacts with a crafted URL or input, the injected script executes in their browser context, potentially leading to session hijacking, credential theft, or manipulation of the web page content. The vulnerability is exploitable remotely over the network without requiring authentication, but it does require user interaction such as clicking a malicious link. The CVSS v3.1 base score is 7.1, indicating high severity, with vector metrics AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L, meaning the attack is network-based, requires low attack complexity, no privileges, user interaction, and impacts confidentiality, integrity, and availability with a scope change. No known exploits have been reported in the wild as of the publication date. The plugin is widely used in WooCommerce-based e-commerce sites to customize registration fields, making the vulnerability relevant to many online stores. The improper input sanitization likely occurs in the handling of registration form fields that are reflected back in the response without adequate encoding or filtering. This vulnerability can be leveraged to steal cookies, perform phishing, or execute arbitrary scripts in the victim's browser, undermining trust and security of affected websites.

For European organizations, especially those operating e-commerce platforms using WooCommerce with the affected plugin, this vulnerability poses significant risks. Attackers can exploit the reflected XSS to hijack user sessions, steal sensitive customer data, or manipulate the user interface to conduct phishing attacks. This can lead to loss of customer trust, regulatory penalties under GDPR due to data breaches, and financial losses from fraud or downtime. The reflected nature of the XSS means attacks often rely on social engineering, but the widespread use of WooCommerce in Europe increases the attack surface. Additionally, the scope change in the CVSS vector indicates that the vulnerability can affect resources beyond the vulnerable component, potentially impacting other parts of the web application or user data. The availability impact, while typically less severe in XSS, could manifest as denial of service through script-induced browser crashes or resource exhaustion. Overall, the vulnerability threatens confidentiality, integrity, and availability of web applications and user data, making it a critical concern for European e-commerce businesses.

1. Immediately monitor for the release of an official patch or update from extendons for the WooCommerce Registration Fields Plugin and apply it as soon as available. 2. Until a patch is released, implement Web Application Firewall (WAF) rules that detect and block reflected XSS payloads targeting the affected plugin's endpoints. 3. Employ Content Security Policy (CSP) headers to restrict the execution of inline scripts and only allow trusted script sources, reducing the impact of injected scripts. 4. Review and sanitize all user inputs on the registration forms, ensuring proper encoding and filtering to prevent script injection. 5. Educate users and staff about the risks of clicking suspicious links to reduce the chance of successful social engineering exploitation. 6. Conduct regular security audits and penetration testing focusing on input validation and output encoding in custom WooCommerce plugins. 7. Monitor web server and application logs for unusual requests or error patterns that may indicate attempted exploitation. 8. Consider temporarily disabling or replacing the vulnerable plugin with an alternative solution if patching is delayed and risk is high.