CVE-2025-49321 is a high-severity security vulnerability classified as CWE-79, which corresponds to Improper Neutralization of Input During Web Page Generation, commonly known as Cross-site Scripting (XSS). This vulnerability affects the Arraytics Eventin product, specifically versions up to 4.0.28. The flaw allows an attacker to inject malicious scripts into web pages generated by the Eventin application, which are then reflected back to users without proper sanitization or encoding. This reflected XSS can be triggered remotely over the network without requiring authentication (AV:N/PR:N), but it does require user interaction (UI:R), such as clicking a crafted link or visiting a malicious page. The vulnerability impacts confidentiality, integrity, and availability to a limited extent, as indicated by the CVSS vector (C:L/I:L/A:L), meaning an attacker can steal sensitive information, manipulate displayed content, or cause partial denial of service. The scope is changed (S:C), indicating that the vulnerability affects components beyond the vulnerable module, potentially impacting other parts of the system or user sessions. No known exploits have been reported in the wild yet, and no official patches have been linked at the time of publication. The vulnerability was reserved and published in June 2025, highlighting its recent discovery. The lack of patch availability necessitates immediate attention to mitigate risk. The vulnerability arises from insufficient input validation and output encoding during web page generation, allowing malicious payloads to be executed in the context of the victim's browser, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of the user.

For European organizations using Arraytics Eventin, this vulnerability poses a significant risk, especially for those relying on the product for event management or related web services. Exploitation could lead to unauthorized access to user sessions, leakage of sensitive information, and manipulation of web content, undermining user trust and compliance with data protection regulations such as GDPR. The reflected XSS can be leveraged in targeted phishing campaigns or drive-by attacks, increasing the attack surface for European enterprises. Additionally, compromised user sessions could facilitate further lateral movement or privilege escalation within organizational networks. The potential for partial denial of service could disrupt critical event operations or customer interactions, impacting business continuity. Given the high CVSS score and scope change, the vulnerability could affect multiple components or integrated systems, amplifying the impact. Organizations in sectors with high regulatory scrutiny, such as finance, healthcare, and government, face heightened risks due to the sensitivity of data handled and the reputational damage from breaches.

Immediate mitigation should focus on implementing strict input validation and output encoding on all user-supplied data within the Eventin application to prevent script injection. Until an official patch is released, organizations should employ Web Application Firewalls (WAFs) configured with rules to detect and block common XSS payloads targeting Eventin endpoints. Security teams should conduct thorough code reviews and penetration testing to identify and remediate similar vulnerabilities in custom integrations or plugins. User awareness training is critical to reduce the risk of successful phishing attacks exploiting this vulnerability. Additionally, organizations should monitor logs for unusual activity indicative of attempted XSS exploitation and isolate affected systems if suspicious behavior is detected. Employing Content Security Policy (CSP) headers can help mitigate the impact by restricting the execution of unauthorized scripts. Finally, organizations should maintain close communication with Arraytics for timely patch releases and apply updates promptly once available.