CVE-2025-46461 is a DOM-based Cross-site Scripting (XSS) vulnerability identified in the Relentless Apps RRSSB product, affecting versions up to and including 1.0.1. The vulnerability arises from improper neutralization of input during web page generation, specifically categorized under CWE-79. DOM-based XSS occurs when client-side scripts write user-controllable data to the Document Object Model (DOM) without proper sanitization or encoding, allowing an attacker to inject malicious scripts that execute in the context of the victim's browser. This can lead to unauthorized actions such as session hijacking, credential theft, or redirection to malicious sites. The vulnerability is present in the RRSSB product, which is a web-based tool or library developed by Relentless Apps, commonly used to generate social sharing buttons or similar UI components. The lack of a patch or fix at the time of publication indicates that the vulnerability remains unmitigated. No known exploits have been reported in the wild, but the nature of DOM-based XSS makes it a significant risk if exploited, especially in environments where RRSSB is integrated into web applications handling sensitive user data or authentication tokens. The vulnerability does not require server-side code execution but relies on client-side script manipulation, making it exploitable through crafted URLs or manipulated input fields that the vulnerable RRSSB component processes.

For European organizations, the exploitation of this DOM-based XSS vulnerability could compromise the confidentiality and integrity of user sessions and data. Attackers could steal session cookies, perform actions on behalf of authenticated users, or inject malicious payloads that spread malware or conduct phishing attacks. This is particularly critical for sectors such as finance, healthcare, and government services where sensitive personal data and critical infrastructure are involved. The vulnerability could also damage organizational reputation and lead to regulatory non-compliance under GDPR if personal data is exposed. Since RRSSB is often embedded in websites to facilitate social sharing, any web-facing application using this component is at risk. The impact is amplified in organizations with large user bases or those relying heavily on web applications for customer interaction. Additionally, the lack of authentication requirements and the client-side nature of the attack vector mean that exploitation can be performed remotely and without prior access, increasing the attack surface.

Given the absence of an official patch, European organizations should implement immediate compensating controls. First, conduct an inventory to identify all web applications using RRSSB and assess exposure. Employ Content Security Policy (CSP) headers with strict script-src directives to limit the execution of unauthorized scripts. Implement input validation and output encoding on all user-controllable inputs processed by RRSSB components, especially those reflected in the DOM. Use security-focused web application firewalls (WAFs) configured to detect and block common XSS payloads targeting RRSSB. Encourage developers to update or replace RRSSB with alternative libraries that have addressed this vulnerability once patches become available. Additionally, monitor web traffic for unusual patterns indicative of XSS exploitation attempts. Educate users about phishing risks that may leverage this vulnerability. Finally, consider sandboxing or isolating the affected components to reduce the impact of potential script execution.