CVE-2025-55182 is a critical vulnerability affecting Meta's React Server Components, specifically versions 19.0.0, 19.1.0, 19.1.1, and 19.2.0, including packages react-server-dom-parcel, react-server-dom-turbopack, and react-server-dom-webpack. The flaw is a deserialization of untrusted data vulnerability (CWE-502) that occurs when the server-side components unsafely deserialize payloads received via HTTP requests targeting Server Function endpoints. Because the deserialization process does not properly validate or sanitize incoming data, an attacker can craft malicious serialized payloads that, when processed by the server, lead to remote code execution (RCE). This vulnerability is exploitable without authentication or user interaction, making it highly dangerous. The CVSS 3.1 score of 10 reflects the vulnerability's ease of exploitation (network attack vector, no privileges required, no user interaction) and its severe impact on confidentiality, integrity, and availability, with a scope that affects the entire vulnerable system. Although no public exploits have been observed yet, the critical nature of this flaw demands immediate attention. React Server Components are increasingly used in modern web applications to improve performance and user experience by rendering components on the server. The affected packages are integral to this architecture, meaning many web applications relying on these versions are exposed. The vulnerability could allow attackers to execute arbitrary code on the server, potentially leading to full system compromise, data theft, or service disruption.

For European organizations, the impact of CVE-2025-55182 is substantial. Organizations using vulnerable React Server Components in their web applications risk remote attackers gaining full control over their backend servers. This can lead to unauthorized access to sensitive data, modification or deletion of critical information, and disruption of services. The vulnerability threatens confidentiality by exposing private data, integrity by allowing unauthorized code execution and data manipulation, and availability by enabling denial-of-service conditions through malicious payloads. Given the widespread adoption of React and server-side rendering techniques in Europe’s digital economy, including e-commerce, finance, healthcare, and government sectors, exploitation could result in significant operational and reputational damage. Additionally, the vulnerability’s pre-authentication nature means attackers can target systems directly without needing credentials, increasing the attack surface. The lack of known exploits currently provides a window for proactive mitigation, but the critical severity necessitates urgent patching and protective measures to prevent potential attacks.

1. Apply patches or updates from Meta as soon as they become available to address the deserialization vulnerability. 2. Until patches are released, restrict network access to Server Function endpoints by implementing firewall rules or network segmentation to limit exposure to untrusted sources. 3. Implement strict input validation and sanitization on all data received by Server Function endpoints to detect and reject malformed or suspicious serialized payloads. 4. Employ runtime application self-protection (RASP) or web application firewalls (WAFs) configured to detect and block deserialization attack patterns. 5. Conduct thorough code reviews and security testing focusing on deserialization logic within React Server Components. 6. Monitor logs and network traffic for unusual activity indicative of exploitation attempts, such as unexpected serialized data or anomalous server behavior. 7. Educate development teams about secure deserialization practices and the risks of processing untrusted data. 8. Consider deploying application-layer authentication or authorization mechanisms on Server Function endpoints to reduce exposure, even though the vulnerability does not require authentication. 9. Prepare incident response plans specifically addressing potential exploitation scenarios involving RCE in server-side components.