CVE-2025-23480 identifies a Stored Cross-site Scripting (XSS) vulnerability in the MicahBlu RSVP ME application, specifically affecting versions up to and including 1.9.9. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, which allows malicious scripts to be stored persistently on the server and executed in the browsers of users who access the affected pages. Stored XSS is particularly dangerous because the malicious payload is saved on the server and delivered to multiple users, increasing the attack surface and potential damage. An attacker could exploit this vulnerability by submitting crafted input that includes executable JavaScript code, which would then be rendered and executed in the context of other users' sessions. This can lead to theft of session cookies, redirection to malicious sites, or execution of unauthorized actions within the application. The vulnerability affects RSVP ME, a web-based event management tool, which may be used by organizations to manage RSVPs and event details. No CVSS score has been assigned yet, and no known exploits have been reported in the wild as of the publication date. The vulnerability was reserved in January 2025 and published in March 2025. The lack of a patch link suggests that a fix may not yet be publicly available, emphasizing the need for interim mitigations.

The impact of this Stored XSS vulnerability is significant for organizations using RSVP ME, as it compromises the confidentiality and integrity of user data and sessions. Attackers can execute arbitrary scripts in the browsers of users, potentially leading to session hijacking, theft of sensitive information such as authentication tokens or personal data, and unauthorized actions performed with the privileges of the victim user. This can result in reputational damage, loss of user trust, and potential regulatory consequences if personal data is exposed. Additionally, the availability of the application could be indirectly affected if attackers use the vulnerability to inject disruptive scripts or conduct phishing campaigns. Since RSVP ME is used for event management, exploitation could disrupt event operations and communications. The lack of known exploits currently reduces immediate risk, but the vulnerability remains a critical threat if left unaddressed, especially as Stored XSS is generally easy to exploit without requiring authentication or complex conditions.

Organizations should prioritize applying official patches from MicahBlu once they become available to fully remediate the vulnerability. Until a patch is released, implement strict input validation on all user-supplied data, ensuring that inputs do not contain executable code or HTML tags. Employ robust output encoding and sanitization techniques on all data rendered in web pages to neutralize any potentially malicious content. Utilize Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of any injected code. Conduct thorough security testing and code reviews focusing on input handling and output generation in RSVP ME. Monitor web server and application logs for unusual input patterns or error messages that could indicate attempted exploitation. Educate users and administrators about the risks of XSS and encourage vigilance against suspicious links or behaviors. Consider deploying Web Application Firewalls (WAFs) with rules designed to detect and block XSS payloads as an additional protective layer.