CVE-2025-64221 is a reflected Cross-site Scripting (XSS) vulnerability identified in the designthemes Reservation Plugin, specifically affecting versions up to and including 1.6. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, which allows attackers to inject malicious JavaScript code that is reflected back to users. When a victim clicks on a crafted URL or interacts with a manipulated input, the malicious script executes within their browser context. This can lead to a range of attacks including session hijacking, theft of cookies or credentials, defacement, or redirection to malicious sites. The vulnerability does not require the attacker to be authenticated, increasing its risk profile, but it does require user interaction to trigger the exploit. As of the publication date, no CVSS score has been assigned, no patches have been released, and no known exploits have been observed in the wild. The plugin is commonly used in WordPress environments to manage reservations and bookings, making websites that rely on this functionality potential targets. The lack of proper input sanitization and output encoding in the plugin's codebase is the root cause, highlighting a common web application security weakness. Organizations using this plugin should prioritize remediation once a patch is available or implement temporary mitigations to reduce exposure.

For European organizations, this vulnerability poses a significant risk to websites that utilize the designthemes Reservation Plugin, particularly those in the hospitality, tourism, and event management sectors where online booking systems are critical. Successful exploitation could compromise user accounts, lead to data theft, and damage organizational reputation. The reflected XSS can be used to steal session cookies, enabling attackers to impersonate legitimate users, or to deliver further malware payloads. This could result in unauthorized access to sensitive customer data, financial information, or internal systems if session credentials are reused. Additionally, the presence of malicious scripts on public-facing websites can lead to blacklisting by search engines and loss of customer trust. Given the plugin’s integration with WordPress, a widely used CMS in Europe, the attack surface is broad. The absence of authentication requirements for exploitation increases the threat level, as attackers can target any visitor to the affected site. The impact extends beyond confidentiality to integrity and availability if attackers deface websites or disrupt booking services.

Immediate mitigation should focus on implementing strict input validation and output encoding on all user-supplied data within the reservation plugin’s code, especially in URL parameters and form inputs. Web application firewalls (WAFs) can be configured to detect and block common XSS attack patterns targeting the plugin. Organizations should monitor web server logs for suspicious requests containing script tags or unusual parameter values. Until an official patch is released, consider disabling or replacing the plugin with a more secure alternative. Security teams should conduct regular vulnerability scans and penetration tests focusing on web application security. Educating users about the risks of clicking on suspicious links can reduce the likelihood of successful exploitation. Additionally, Content Security Policy (CSP) headers can be deployed to restrict the execution of unauthorized scripts. Once a patch is available, prompt application of updates is critical. Backup procedures should be reviewed to ensure rapid recovery in case of compromise.