CVE-2025-3598 is a reflected Cross-Site Scripting (XSS) vulnerability identified in the Coupon Affiliates – Affiliate Plugin for WooCommerce, a WordPress plugin used to manage affiliate marketing and coupon distribution. The vulnerability exists due to improper neutralization of input during web page generation, specifically involving the commission_summary parameter. This parameter is not adequately sanitized or escaped before being included in the HTML output, allowing attackers to inject arbitrary JavaScript code. Since the vulnerability is reflected, the malicious script is embedded in a crafted URL or request and executed when a victim clicks the link, without requiring authentication. The vulnerability affects all versions up to and including 6.3.0. The CVSS 3.1 base score is 6.1, reflecting medium severity with network attack vector, low attack complexity, no privileges required, but requiring user interaction. The scope is changed (S:C) because the vulnerability affects resources beyond the initially vulnerable component, potentially impacting the entire web application context. The impact includes limited confidentiality and integrity loss but no availability impact. No patches or fixes are currently linked, and no known exploits have been reported in the wild, though the risk remains significant due to the widespread use of WooCommerce and the plugin in e-commerce sites. The vulnerability can be exploited to steal cookies, session tokens, or perform actions on behalf of the user, potentially leading to account compromise or fraudulent transactions.

The primary impact of this vulnerability is on the confidentiality and integrity of user data and sessions. Attackers can execute arbitrary scripts in the context of the affected website, enabling theft of sensitive information such as authentication cookies, personal data, or affiliate commission details. This can lead to session hijacking, unauthorized actions performed on behalf of users, or redirection to malicious sites. For e-commerce platforms relying on this plugin, such attacks can undermine customer trust, cause financial losses, and damage brand reputation. The vulnerability does not directly affect availability but can facilitate further attacks that might disrupt services. Given the unauthenticated nature of the exploit and the requirement for user interaction, phishing or social engineering campaigns could be used to increase exploitation success. Organizations worldwide using WooCommerce with this plugin are at risk, especially those with significant affiliate marketing operations. The medium severity score reflects a moderate but actionable threat that requires timely remediation to prevent exploitation.

1. Immediate mitigation involves updating the Coupon Affiliates – Affiliate Plugin for WooCommerce to a patched version once available. Since no patch links are currently provided, monitor vendor announcements closely. 2. Implement Web Application Firewall (WAF) rules to detect and block malicious payloads targeting the commission_summary parameter, focusing on suspicious script tags or JavaScript event handlers. 3. Employ Content Security Policy (CSP) headers to restrict execution of inline scripts and loading of untrusted resources, mitigating impact if exploitation occurs. 4. Sanitize and validate all user inputs on the server side, ensuring that any parameters reflected in responses are properly escaped using context-appropriate encoding. 5. Educate users and staff about phishing risks and suspicious links to reduce the likelihood of successful social engineering. 6. Conduct regular security audits and penetration testing focusing on input validation and output encoding in all plugins and custom code. 7. Consider temporarily disabling or replacing the vulnerable plugin if immediate patching is not possible, especially on high-value or public-facing sites. 8. Monitor logs for unusual requests containing suspicious parameters or payloads targeting this vulnerability. These steps go beyond generic advice by focusing on specific parameters, plugin context, and layered defenses.