CVE-2025-62135 identifies a DOM-based Cross-site Scripting (XSS) vulnerability in the landwire Responsive Block Control product, versions up to 1.2.9. This vulnerability stems from improper neutralization of input during web page generation, classified under CWE-79. Specifically, the product fails to adequately sanitize or encode user-supplied data before incorporating it into the Document Object Model (DOM), enabling attackers to inject malicious JavaScript code that executes in the context of the victim's browser. The attack vector is network-based with low complexity, requiring the attacker to have some privileges (PR:L) and user interaction (UI:R), such as tricking a user into clicking a crafted link. The vulnerability impacts confidentiality, integrity, and availability, as malicious scripts can steal session tokens, manipulate page content, or perform actions on behalf of the user. The CVSS v3.1 score of 6.5 reflects a medium severity level with a scope change (S:C), indicating that the vulnerability affects components beyond the initially vulnerable scope. No patches or known exploits are currently available, but the vulnerability is publicly disclosed and should be addressed promptly. The issue is relevant for web applications using Responsive Block Control, which may be embedded in various websites or portals, potentially exposing users to XSS attacks that can lead to account compromise or data leakage.

For European organizations, this vulnerability poses risks primarily to web applications utilizing the landwire Responsive Block Control component. Successful exploitation can lead to session hijacking, unauthorized actions performed on behalf of users, theft of sensitive information, and potential defacement or disruption of web services. This can damage organizational reputation, lead to regulatory non-compliance (e.g., GDPR breaches if personal data is compromised), and cause operational disruptions. Sectors such as finance, healthcare, government, and e-commerce, which rely heavily on secure web interfaces, are particularly vulnerable. The medium severity rating indicates that while the vulnerability is not trivial, it requires some level of privilege and user interaction, somewhat limiting mass exploitation but still posing a significant threat in targeted attacks. The absence of known exploits in the wild reduces immediate risk but does not eliminate the need for proactive mitigation. European organizations with public-facing web portals or intranet systems incorporating this product should prioritize remediation to prevent exploitation.

1. Monitor landwire's official channels for patches addressing CVE-2025-62135 and apply them promptly once available. 2. Implement strict input validation and output encoding on all user-supplied data to prevent injection of malicious scripts, focusing on the DOM context. 3. Deploy Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS attacks. 4. Conduct thorough code reviews and security testing of web applications integrating Responsive Block Control to identify and remediate similar input handling issues. 5. Educate users about the risks of clicking on suspicious links to mitigate the user interaction requirement for exploitation. 6. Use web application firewalls (WAFs) with rules tailored to detect and block XSS attack patterns targeting this component. 7. Regularly audit web server and application logs for unusual activity indicative of attempted exploitation. 8. Consider isolating or sandboxing components that handle untrusted input to limit the scope of potential attacks.