CVE-2025-52750 is a reflected Cross-site Scripting (XSS) vulnerability found in the Emu2 email user management software developed by Juergen Schulze. The vulnerability arises from improper neutralization of user-supplied input during web page generation, specifically in the emu2-email-users-2 component. This flaw allows attackers to craft malicious URLs or input that, when processed by the vulnerable Emu2 versions (up to 0.83b), results in the injection and execution of arbitrary JavaScript code in the context of the victim's browser. The vulnerability has a CVSS v3.1 base score of 7.1, indicating high severity, with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L. This means the attack can be performed remotely over the network without any privileges, requires low attack complexity, no prior authentication, but does require user interaction (e.g., clicking a malicious link). The scope is changed, indicating the vulnerability affects resources beyond the vulnerable component, potentially impacting the entire web application session. The consequences include partial loss of confidentiality, integrity, and availability, as the injected scripts could steal session cookies, manipulate page content, or perform actions on behalf of the user. Although no known exploits are currently reported in the wild, the public disclosure and high CVSS score suggest attackers may develop exploits soon. The vulnerability affects all Emu2 versions up to 0.83b, with no patch links currently available, indicating users must implement interim mitigations until official fixes are released.

For European organizations, the impact of CVE-2025-52750 can be significant, especially for those relying on Emu2 for email user management. Successful exploitation could allow attackers to execute arbitrary scripts in users' browsers, leading to session hijacking, credential theft, phishing, or unauthorized actions within the affected web application. This can compromise sensitive communications and user data, potentially violating GDPR and other data protection regulations. The reflected XSS nature means the attack requires user interaction, but targeted phishing campaigns could increase success rates. Disruption of email user management could also affect operational continuity. Organizations in sectors with high email dependency, such as finance, government, and critical infrastructure, face elevated risks. The vulnerability's ability to affect confidentiality, integrity, and availability simultaneously amplifies its threat. Additionally, the scope change in the CVSS vector suggests that the impact may extend beyond the immediate vulnerable component, potentially affecting broader application functionality and user trust.

To mitigate CVE-2025-52750, European organizations should first verify if they use Emu2 versions up to 0.83b and prioritize upgrading to a patched version once available. In the absence of an official patch, implement strict input validation and output encoding on all user-supplied data within the emu2-email-users-2 component to neutralize malicious scripts. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. Educate users about the risks of clicking suspicious links and encourage cautious behavior regarding unsolicited emails or messages. Monitor web application logs for unusual input patterns or repeated attempts to exploit XSS. Consider deploying Web Application Firewalls (WAFs) with rules designed to detect and block reflected XSS payloads targeting Emu2. Regularly review and update security policies to incorporate emerging threat intelligence related to this vulnerability. Finally, coordinate with the vendor or community to obtain patches or security advisories promptly.