CVE-2025-11149 is a high-severity Denial of Service (DoS) vulnerability affecting all versions of the node-static package, including @nubosoftware/node-static. The vulnerability arises because the package fails to properly handle exceptions when user input contains null bytes (\x00). Specifically, when an attacker sends a request to the server with a URL containing a null byte, such as http://host/%00, the server throws an uncaught exception, causing the node-static server to crash and become unavailable. This vulnerability is classified under CWE-400 (Uncontrolled Resource Consumption) because the server's failure to handle malformed input leads to resource exhaustion or service disruption. The CVSS v3.1 base score is 7.5, indicating a high severity level. The attack vector is network-based (AV:N), requires no privileges (PR:N), no user interaction (UI:N), and affects the availability (A:H) of the service without impacting confidentiality or integrity. The vulnerability is exploitable remotely and easily, as it requires only a specially crafted HTTP request containing a null byte. No patches or fixes are currently available, and no known exploits have been reported in the wild as of the publication date. The node-static package is a widely used simple static file server for Node.js environments, often employed in development and lightweight production scenarios to serve static content. The failure to handle null byte input properly indicates a lack of input validation and exception handling in the package's request processing logic, which attackers can leverage to cause service outages.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on node-static to serve static content in web applications, internal tools, or development environments. A successful DoS attack exploiting this vulnerability would result in server crashes and service unavailability, potentially disrupting business operations, customer-facing services, or internal workflows. Although the vulnerability does not compromise data confidentiality or integrity, the loss of availability can lead to reputational damage, financial losses due to downtime, and increased operational costs for incident response and recovery. Organizations with automated deployment pipelines or CI/CD systems using node-static for artifact hosting or static content delivery may face interruptions in their development lifecycle. Additionally, the ease of exploitation and lack of required authentication increase the risk of opportunistic attacks by malicious actors scanning for vulnerable servers. Given that no patches are currently available, organizations must rely on mitigation strategies to reduce exposure. The impact is more pronounced in sectors where uptime and service reliability are critical, such as e-commerce, financial services, healthcare, and public sector services across Europe.

To mitigate the risk posed by CVE-2025-11149, European organizations should implement the following specific measures: 1) Immediately audit all systems and applications to identify instances of node-static or @nubosoftware/node-static usage, including transitive dependencies in development and production environments. 2) Where possible, replace node-static with alternative static file servers that have robust input validation and exception handling, such as NGINX, Apache HTTP Server, or other well-maintained Node.js static server packages with active security maintenance. 3) Implement web application firewalls (WAFs) or reverse proxies configured to detect and block HTTP requests containing null bytes or other suspicious malformed inputs before they reach the node-static server. 4) Employ network-level filtering to restrict access to node-static servers, limiting exposure to trusted IP ranges or internal networks only, thereby reducing the attack surface. 5) Enhance monitoring and alerting to detect abnormal server crashes or repeated requests containing null bytes, enabling rapid incident response. 6) Engage with the node-static package maintainers or community to track the release of patches or updates addressing this vulnerability and plan for timely upgrades once available. 7) For development environments, consider sandboxing or isolating node-static instances to minimize impact in case of exploitation. These targeted mitigations go beyond generic advice by focusing on immediate risk reduction through architectural changes, filtering, and monitoring tailored to the specific nature of the vulnerability.