CVE-2025-48068 is a security vulnerability identified in the Next.js framework, a popular React-based tool used for building full-stack web applications. The vulnerability arises from missing origin validation in the WebSocket implementation when running the development server with the App Router enabled. Specifically, in Next.js versions from 13.0 up to but not including 14.2.30, and versions from 15.0.0 up to but not including 15.2.2, an attacker can cause limited source code exposure. This exposure occurs only in local development environments when the developer is running the server using the 'npm run dev' command. Exploitation requires the developer to visit a malicious webpage while the vulnerable dev server is active. The vulnerability is classified under CWE-1385 (Missing Origin Validation), indicating that the WebSocket server does not properly verify the origin of incoming connections, allowing unauthorized access to sensitive development data. The issue has been addressed and patched in Next.js versions 14.2.30 and 15.2.2. The CVSS 4.0 base score is 2.3, reflecting a low severity level due to the limited scope and conditions required for exploitation. There are no known exploits in the wild, and the vulnerability does not affect production environments, only local development setups. This limits the risk primarily to developers who may inadvertently expose source code by interacting with malicious web content during active development sessions.

For European organizations, the impact of CVE-2025-48068 is relatively low but still noteworthy. Since the vulnerability only affects local development environments and requires user interaction (visiting a malicious webpage), the risk of widespread exploitation is limited. However, organizations with active development teams using vulnerable Next.js versions could face limited source code exposure, potentially leaking proprietary or sensitive application logic. This could aid attackers in crafting more effective attacks against production systems if the leaked code contains security flaws or sensitive business logic. The impact is primarily on confidentiality, with no direct effect on integrity or availability. Given the vulnerability does not affect production deployments, operational disruption is unlikely. Nonetheless, organizations with strict data protection requirements or intellectual property concerns should consider this vulnerability seriously to prevent inadvertent leaks during development. The low CVSS score aligns with the limited impact, but the risk is amplified if developers are not aware of the need to update or avoid visiting untrusted websites during development.

To mitigate this vulnerability, European organizations should take the following specific actions: 1) Upgrade all Next.js development environments to version 14.2.30 or later, or 15.2.2 or later, where the vulnerability is patched. 2) Educate developers about the risks of running development servers exposed to untrusted networks or visiting unknown websites while the dev server is active. 3) Implement network segmentation or firewall rules to restrict access to development servers, ensuring they are not reachable from external or untrusted networks. 4) Use secure development practices such as running development environments within isolated containers or virtual machines to limit exposure. 5) Monitor developer workstations for unusual network activity during development sessions. 6) Encourage the use of VPNs or secure tunnels when remote development is necessary to reduce exposure to malicious web content. 7) Incorporate security scanning tools in the development pipeline to detect outdated dependencies and enforce timely updates. These measures go beyond generic advice by focusing on controlling the development environment exposure and developer behavior, which are critical given the nature of this vulnerability.