CVE-2025-55184 is a vulnerability identified in Meta's React Server Components, specifically in versions 19.0.0, 19.0.1, 19.1.0, 19.1.1, 19.1.2, 19.2.0, and 19.2.1, affecting packages such as react-server-dom-parcel, react-server-dom-turbopack, and react-server-dom-webpack. The root cause is unsafe deserialization of untrusted data received via HTTP requests directed at Server Function endpoints. Deserialization is the process of converting data from a format suitable for transmission or storage back into an object or data structure. When this process is performed without proper validation or sanitization, it can lead to severe security issues. In this case, maliciously crafted payloads can cause the server to enter an infinite loop, exhausting resources and causing the server process to hang. This results in a denial of service condition where legitimate HTTP requests cannot be served, impacting the availability of web applications relying on these components. The vulnerability is exploitable remotely without any authentication or user interaction, increasing its risk profile. The CVSS v3.1 base score is 7.5 (high), reflecting the network attack vector, low attack complexity, no privileges required, no user interaction, and a significant impact on availability. Although no public exploits have been reported yet, the vulnerability's nature makes it a critical concern for organizations using these React Server Components in production environments. The issue is related to CWE-502 (Deserialization of Untrusted Data) and CWE-400 (Uncontrolled Resource Consumption), both well-known classes of vulnerabilities that can lead to denial of service or remote code execution in other contexts. The lack of patches at the time of reporting means organizations must rely on mitigations until official fixes are released.

For European organizations, the primary impact of CVE-2025-55184 is denial of service, which can disrupt web services and applications built using affected React Server Components. This can lead to downtime, loss of customer trust, and potential financial losses, especially for e-commerce, online services, and critical infrastructure relying on these technologies. The vulnerability’s pre-authentication nature means attackers can exploit it without credentials, increasing the risk of widespread attacks. Organizations with high traffic websites or those providing essential services may experience significant operational disruptions. Additionally, prolonged outages could affect compliance with European regulations such as GDPR if service availability commitments are not met. The impact is mostly on availability; confidentiality and integrity are not directly affected. The risk is heightened in countries with large digital economies and extensive use of React-based frameworks in web development, where attackers may target high-profile or critical service providers to maximize disruption.

1. Monitor Meta’s official channels for patches addressing CVE-2025-55184 and apply them promptly once available. 2. Until patches are released, implement strict input validation and sanitization on all data received by Server Function endpoints to prevent malicious payloads from triggering unsafe deserialization. 3. Deploy Web Application Firewalls (WAFs) with custom rules to detect and block suspicious payloads targeting react-server-dom-webpack endpoints. 4. Implement rate limiting on HTTP requests to Server Function endpoints to reduce the risk of resource exhaustion from repeated malicious requests. 5. Consider isolating or sandboxing the server processes handling deserialization to limit the impact of potential infinite loops or hangs. 6. Conduct thorough code reviews and security testing focusing on deserialization logic in React Server Components. 7. Prepare incident response plans to quickly identify and mitigate denial of service attacks exploiting this vulnerability. 8. Educate development teams about the risks of unsafe deserialization and best practices for secure coding in React Server Components.