CVE-2025-46510 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the harrysudana Contact Form 7 Calendar plugin, specifically affecting versions up to 3.0.1. The vulnerability allows an attacker to perform unauthorized actions on behalf of an authenticated user by exploiting the lack of proper CSRF protections. This flaw leads to stored Cross-Site Scripting (XSS), where malicious scripts injected via the contact form calendar can be persistently stored and executed in the context of users visiting the affected site. The stored XSS can be leveraged to hijack user sessions, steal cookies, or perform other malicious activities within the victim's browser. The vulnerability arises because the plugin does not adequately verify the origin or intent of requests modifying calendar data, allowing attackers to craft malicious requests that are executed when an authenticated user interacts with the vulnerable component. Although no known exploits are currently reported in the wild, the presence of stored XSS combined with CSRF significantly raises the risk profile, especially for websites relying on this plugin for user interaction and data collection. The plugin is commonly used in WordPress environments to enhance Contact Form 7 functionality by adding calendar features, which means a broad range of websites, including business, governmental, and personal sites, could be impacted if they have not updated or patched the plugin. The vulnerability does not require user interaction beyond the victim visiting a maliciously crafted page, and it does not require elevated privileges beyond those of an authenticated user, making exploitation feasible in many scenarios.

For European organizations, the impact of CVE-2025-46510 can be significant, especially for those relying on WordPress sites with the Contact Form 7 Calendar plugin for customer engagement, appointment scheduling, or data collection. Exploitation could lead to unauthorized actions performed under the guise of legitimate users, resulting in data manipulation, unauthorized data disclosure, or session hijacking. Stored XSS can facilitate further attacks such as phishing, malware distribution, or lateral movement within an organization's web infrastructure. This can undermine user trust, lead to regulatory non-compliance (e.g., GDPR breaches due to data leakage), and cause reputational damage. Organizations in sectors such as healthcare, finance, government, and e-commerce, which often use web forms for sensitive data collection, are particularly at risk. Additionally, the vulnerability could be leveraged as an initial attack vector to gain deeper access into internal networks or to compromise privileged accounts if administrative users are targeted. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the potential for future attacks, especially as exploit code may be developed and shared rapidly once the vulnerability becomes public knowledge.

1. Immediate update or patching: Organizations should monitor the harrysudana Contact Form 7 Calendar plugin for official patches or updates addressing CVE-2025-46510 and apply them promptly. 2. Implement Web Application Firewall (WAF) rules: Deploy WAF rules to detect and block suspicious CSRF and XSS payloads targeting the plugin’s endpoints. Custom rules can be created to inspect request origins and block unauthorized POST requests. 3. Enforce strict Content Security Policy (CSP): Configure CSP headers to restrict the execution of inline scripts and limit sources of executable code, mitigating the impact of stored XSS. 4. Harden authentication and session management: Use multi-factor authentication for administrative users and ensure session tokens are properly invalidated to reduce the risk of session hijacking. 5. Conduct regular security audits: Perform code reviews and penetration testing focusing on web forms and plugins to identify and remediate similar vulnerabilities proactively. 6. Educate users and administrators: Raise awareness about phishing and social engineering attacks that could exploit this vulnerability. 7. Disable or replace the plugin if patching is not immediately possible: Consider alternative calendar plugins with better security track records or temporarily disable the vulnerable functionality to reduce exposure.