CVE-2025-62042 is a cross-site scripting (XSS) vulnerability identified in the Event post product developed by Bastien Ho, affecting versions up to and including 5.10.3. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, which allows an attacker to inject malicious scripts into event posts. When a victim user views the compromised event post, the malicious script executes in their browser context. The CVSS 3.1 vector indicates that the attack can be performed remotely over the network (AV:N) with low attack complexity (AC:L), requiring low privileges (PR:L) and user interaction (UI:R). The scope is changed (S:C), meaning the vulnerability affects resources beyond the initially vulnerable component. The impact includes low confidentiality, integrity, and availability losses (C:L/I:L/A:L). Although no known exploits are currently reported in the wild, the vulnerability could be leveraged for session hijacking, credential theft, or delivering further malware payloads. The vulnerability affects organizations that use the Event post product for managing event-related content, potentially exposing users who interact with maliciously crafted posts. The lack of available patches at the time of reporting necessitates immediate attention to mitigation strategies.

For European organizations, the impact of CVE-2025-62042 can be significant, particularly for those relying on the Event post product for event management and communication. Successful exploitation could lead to unauthorized disclosure of sensitive information, manipulation of event content, or disruption of service availability. This could damage organizational reputation, lead to data breaches involving personal or corporate information, and facilitate further attacks such as phishing or malware distribution. The medium severity rating reflects the need for vigilance, especially in sectors with high regulatory requirements for data protection such as finance, healthcare, and government. Additionally, organizations with large user bases interacting with event posts are at increased risk of widespread impact. The vulnerability’s requirement for user interaction means social engineering tactics could be employed to increase exploitation success. The changed scope of the vulnerability suggests that the attack could affect multiple components or users beyond the initially targeted system, amplifying potential damage.

1. Apply patches or updates from the vendor as soon as they become available to address the vulnerability directly. 2. In the absence of patches, implement strict input validation on all user-supplied data fields related to event posts, ensuring that scripts or HTML tags are sanitized or escaped properly. 3. Employ output encoding techniques on all dynamic content rendered in web pages to prevent script execution. 4. Restrict user permissions to limit who can create or edit event posts, minimizing the risk of malicious input insertion. 5. Use Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. 6. Educate users about the risks of interacting with suspicious event posts and encourage reporting of unusual behavior. 7. Monitor logs and web traffic for signs of attempted XSS exploitation or anomalous activity related to event posts. 8. Consider deploying web application firewalls (WAFs) with rules tailored to detect and block XSS payloads targeting the Event post product. 9. Regularly review and audit the codebase and configurations of the Event post installation to ensure secure coding practices are followed.