CVE-2025-49342 identifies a Cross-Site Request Forgery (CSRF) vulnerability in the Wolfgang Häfelinger Custom Style product, a tool used for customizing web application styles. The vulnerability stems from insufficient validation of user requests, allowing attackers to craft malicious requests that, when executed by an authenticated user, perform unauthorized actions on their behalf. This CSRF flaw is compounded by the presence of stored Cross-Site Scripting (XSS), meaning that the malicious payload can be permanently stored on the server and served to other users, amplifying the attack impact. The vulnerability affects all versions up to 1.0, with no patches currently available. The CVSS 3.1 base score of 7.1 reflects a high severity, with an attack vector of network (remote exploitation), low attack complexity, no privileges required, but requiring user interaction. The scope is changed, indicating that the vulnerability affects resources beyond the initially vulnerable component. The impact includes partial loss of confidentiality, integrity, and availability, as attackers can inject scripts to steal sensitive data, manipulate content, or disrupt services. No known exploits have been reported in the wild, but the vulnerability's nature and severity make it a significant risk. The CWE-352 classification confirms the CSRF nature of the issue, which is a common web security problem where state-changing requests are not properly protected against unauthorized execution. The lack of patch links suggests that users must implement interim mitigations until an official fix is released.

For European organizations, this vulnerability poses a significant risk to web applications utilizing the Wolfgang Häfelinger Custom Style product. Exploitation can lead to unauthorized actions performed with the privileges of authenticated users, potentially resulting in data theft, session hijacking, defacement, or service disruption. The stored XSS aspect increases the risk by enabling persistent malicious scripts that can affect multiple users and systems. Sensitive sectors such as finance, healthcare, and government agencies are particularly vulnerable due to the potential exposure of confidential data and critical services. The attack requires user interaction but no elevated privileges, making it easier for attackers to exploit through phishing or social engineering campaigns. The absence of patches means organizations must rely on compensating controls, increasing operational overhead and risk exposure. Additionally, the changed scope indicates that the vulnerability could impact multiple components or services, broadening the potential damage. Overall, the vulnerability threatens confidentiality, integrity, and availability of affected systems, with potential regulatory and reputational consequences under European data protection laws such as GDPR.

European organizations should implement the following specific mitigations: 1) Deploy anti-CSRF tokens in all state-changing web requests to ensure that requests originate from legitimate users. 2) Enforce strict input validation and output encoding to prevent stored XSS payloads from executing. 3) Monitor user interactions and anomalous request patterns to detect potential CSRF exploitation attempts. 4) Apply Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts. 5) Educate users about phishing and social engineering risks that could trigger CSRF attacks. 6) Isolate the Custom Style component within web applications to limit the scope of potential compromise. 7) Regularly review and update web application firewalls (WAFs) to detect and block CSRF and XSS attack vectors. 8) Maintain an inventory of affected systems to prioritize patching once official updates become available. 9) Consider temporary disabling or restricting the use of the Custom Style product if feasible until a patch is released. These measures go beyond generic advice by focusing on layered defenses tailored to the specific vulnerability characteristics.