CVE-2025-49047 is a medium severity vulnerability classified as CWE-79, indicating an Improper Neutralization of Input During Web Page Generation, commonly known as Cross-site Scripting (XSS). This vulnerability affects the keeross DigitalOcean Spaces Sync product up to version 2.2.1. The issue allows an attacker to inject malicious scripts that are stored and later executed in the context of a victim's browser when they access affected web pages generated by the application. Specifically, this is a Stored XSS vulnerability, meaning that the malicious payload is saved on the server side (e.g., in a database or persistent storage) and served to users without proper sanitization or encoding. The CVSS v3.1 base score is 5.9, reflecting a medium severity level. The vector string (CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L) indicates that the attack can be performed remotely over the network without physical access, requires low attack complexity, but needs high privileges and user interaction. The scope is changed (S:C), meaning the vulnerability affects resources beyond the initially vulnerable component. The impact affects confidentiality, integrity, and availability at a low level. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability arises from insufficient input validation or output encoding during web page generation, allowing malicious JavaScript to be stored and executed in users' browsers, potentially leading to session hijacking, data theft, or unauthorized actions performed on behalf of the user.

For European organizations using keeross DigitalOcean Spaces Sync, this vulnerability poses a risk of client-side attacks that can compromise user sessions, steal sensitive information, or perform unauthorized actions within the context of the affected web application. Since the vulnerability requires high privileges to exploit, it is likely that attackers would need to have some level of authenticated access to inject malicious scripts, limiting the attack surface to internal or trusted users or attackers who have compromised credentials. However, once exploited, the Stored XSS can affect multiple users, potentially leading to broader compromise. The change of scope (S:C) means that the impact could extend beyond the immediate application, possibly affecting other integrated systems or services. European organizations handling sensitive or regulated data (e.g., personal data under GDPR) could face compliance risks and reputational damage if such an attack leads to data leakage or unauthorized access. Additionally, the availability impact, while low, could disrupt business operations if exploited to perform denial-of-service or degrade user trust in the service.

Given the nature of this Stored XSS vulnerability, European organizations should implement the following specific mitigations: 1) Apply strict input validation and output encoding on all user-supplied data before rendering it in web pages, using context-aware encoding libraries to neutralize script injection. 2) Enforce Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS payloads. 3) Limit the privileges required to perform actions that can inject content, reducing the risk that high-privilege accounts are compromised or misused. 4) Conduct thorough code reviews and security testing focusing on input handling and output generation in the DigitalOcean Spaces Sync integration. 5) Monitor logs and user activity for suspicious behavior indicative of attempted or successful XSS exploitation. 6) Since no patch is currently linked, organizations should engage with the vendor or community to obtain updates or workarounds and consider temporary mitigations such as disabling affected features or restricting access to trusted users only. 7) Educate users about the risks of interacting with suspicious content and encourage the use of updated browsers with built-in XSS protections.