CVE-2025-55887 is a Cross-Site Scripting (XSS) vulnerability identified in the meal reservation service ARD. The vulnerability specifically affects the transaction confirmation page, where the transactionID parameter in the HTTP GET request is not properly validated or encoded before being reflected in the page output. This improper input handling allows an attacker to inject malicious JavaScript code that executes in the context of the victim's browser session. Successful exploitation can lead to session hijacking, theft of authentication cookies, and execution of arbitrary actions on behalf of the user without their consent. The vulnerability is categorized under CWE-79, which covers improper neutralization of input during web page generation. The CVSS v3.1 base score is 6.1, indicating a medium severity level. The vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N) shows that the attack can be performed remotely over the network without privileges, requires user interaction (clicking a crafted link), and affects confidentiality and integrity with a scope change, but does not impact availability. No patches or known exploits in the wild have been reported yet. The vulnerability was published on September 22, 2025, and was reserved on August 16, 2025. The lack of affected version details suggests the need for further vendor communication to identify impacted releases.

For European organizations, this vulnerability poses a significant risk especially to entities relying on the ARD meal reservation service, which may be used in corporate cafeterias, universities, or public institutions. Exploitation could lead to unauthorized access to user sessions, enabling attackers to impersonate legitimate users, steal sensitive personal data, or manipulate transactions. This can result in privacy breaches under GDPR regulations, reputational damage, and potential financial losses. The scope change in the CVSS vector indicates that the vulnerability can affect resources beyond the initially vulnerable component, potentially compromising other parts of the web application or user data. Given the medium severity, the threat is non-trivial but requires user interaction, which may limit large-scale automated exploitation. However, targeted phishing campaigns or social engineering could increase risk. The absence of known exploits in the wild currently reduces immediate threat but does not preclude future exploitation. Organizations in Europe must consider the regulatory implications of data breaches and the importance of protecting user trust in digital services.

To mitigate CVE-2025-55887, organizations should implement strict input validation and output encoding on the transactionID parameter and any other user-controllable inputs. Employing context-aware encoding libraries such as OWASP Java Encoder or similar frameworks can prevent injection of executable scripts. Web application firewalls (WAFs) should be configured to detect and block suspicious payloads targeting the transactionID parameter. Additionally, implementing Content Security Policy (CSP) headers can reduce the impact of XSS by restricting the execution of unauthorized scripts. User education to recognize phishing attempts and suspicious links is also critical since exploitation requires user interaction. Regular security testing, including automated scanning and manual penetration testing focused on XSS vulnerabilities, should be conducted. Finally, organizations should engage with the ARD service provider to obtain patches or updates and monitor for any future exploit disclosures.