CVE-2025-52753 is a reflected Cross-site Scripting (XSS) vulnerability in the 'Contact Form by Supsystic' WordPress plugin, affecting versions up to and including 1.7.35. The vulnerability arises from improper neutralization of user-supplied input during web page generation, allowing attackers to inject malicious JavaScript code into URLs or form inputs that are reflected back to users without proper sanitization or encoding. When a victim clicks a crafted link or submits a manipulated form, the malicious script executes in their browser context, potentially enabling theft of cookies, session tokens, or other sensitive information, as well as performing actions on behalf of the user (e.g., CSRF attacks). The vulnerability requires no authentication but does require user interaction (clicking a malicious link or submitting a form). The CVSS v3.1 base score is 7.1, reflecting network attack vector, low attack complexity, no privileges required, user interaction needed, and impacts on confidentiality, integrity, and availability with scope change. Although no known exploits are currently reported in the wild, the public disclosure and ease of exploitation make this a significant threat. The plugin is widely used in WordPress environments, which are common in European organizations for public websites and customer interaction portals, increasing the risk of exploitation. The vulnerability was reserved in June 2025 and published in October 2025, with no patch links currently available, indicating that organizations must monitor for updates or apply temporary mitigations.

For European organizations, this vulnerability poses a significant risk to the confidentiality, integrity, and availability of web applications using the affected plugin. Attackers can exploit the reflected XSS to hijack user sessions, steal credentials, or deliver malicious payloads, potentially leading to unauthorized access or data breaches. Public-facing websites, especially those handling sensitive customer data or providing critical services, could suffer reputational damage and regulatory penalties under GDPR if user data is compromised. The attack requires user interaction but no authentication, making it easier for attackers to target a broad audience via phishing or social engineering. The scope change in the CVSS vector indicates that the vulnerability could affect components beyond the immediate plugin, potentially impacting the entire WordPress site. Given the widespread use of WordPress and this plugin in Europe, especially in sectors like e-commerce, government, and education, the impact could be substantial if exploited at scale.

European organizations should prioritize the following mitigations: 1) Monitor the vendor’s official channels for patches and apply updates to Contact Form by Supsystic immediately once available. 2) Until a patch is released, implement Web Application Firewall (WAF) rules to detect and block typical XSS attack patterns targeting the plugin’s endpoints. 3) Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. 4) Conduct input validation and output encoding on all user-supplied data in custom code interfacing with the plugin. 5) Educate users and administrators about phishing risks to reduce the likelihood of successful social engineering attacks exploiting this vulnerability. 6) Regularly audit WordPress plugins for vulnerabilities and remove or replace those that are unmaintained or high-risk. 7) Use security plugins that can detect and mitigate XSS attempts dynamically. These steps go beyond generic advice by focusing on layered defenses and proactive monitoring tailored to the plugin’s context.