Security | Threat Detection | Cyberattacks | DevSecOps | Compliance

On December 3rd, CVE-2025-55182 was published by CISA. This CVSS 10.0 vulnerability allows unauthenticated remote code execution, where a threat actor can exploit a flaw in React’s process to decode payloads sent to React Server Function endpoints. It is important to note that while not every team is using React Server Function endpoints in their app, they still may be vulnerable if their app supports React Server Components.

On December 3, 2025, React maintainers disclosed a critical unauthenticated remote code execution (RCE) vulnerability in React Server Components (RSC), tracked as CVE-2025-55182. A working PoC was released publicly, and Wallarm immediately began observing widespread exploitation attempts across customer environments.

On December 3, 2025, the React team released fixes for a maximum severity vulnerability in React Server Components (RSC). The vulnerability, tracked as CVE-2025-55182, stems from unsafe handling of serialized DOM elements, allowing for remote code execution in React 19 and other frameworks built on top of it, such as Next.js 15–16. The vulnerability was responsibly disclosed to React as part of a bug bounty program and is not known to be actively exploited in the wild at this time.

A critical vulnerability, CVE-2025-66478, has been identified in Next.js applications using React Server Components (RSC) with the App Router. This vulnerability receives a CVSS score of 10.0 and a Bitsight Dynamic Vulnerability Exploit (DVE) score of 7.85. This vulnerability may allow remote code execution (RCE) when affected servers process attacker-controlled RSC requests. CVE-2025-66478 is tied to an upstream React issue (CVE-2025-55182–DVE score 9.15) affecting the RSC protocol implementation.

On December 3, 2025, the React team disclosed CVE-2025-55182, a critical remote code execution vulnerability in React Server Components. The flaw carries a CVSS score of 10.0, the maximum severity rating. What makes this vulnerability particularly dangerous is its simplicity: attackers only need to send a single crafted HTTP request to gain complete control over vulnerable servers. No authentication required. No complex exploit chains. Just one malicious request.

On December 3 2025, the React team released patched versions of the affected React Server Components packages. Framework vendors, including Next.js, provided updated builds on the same day. Any environment using React Server Components or frameworks that embed the RSC pipeline should.

On 29 November 2025, researcher Lachlan Davidson reported a critical React vulnerability that allows unauthenticated remote code execution via specially crafted React Server Function payloads. This vulnerability was disclosed as CVE-2025-55182 (React) and CVE-2025-66478 (Next.js) and is rated CVSS 10.0. A public proof concept has also been released so patching is of utmost importance.

Designated CVE-2025-55182 and widely dubbed "React2Shell," this vulnerability represents a worst-case scenario for modern web applications: Unauthenticated Remote Code Execution (RCE) on default configurations.

Cloudflare has deployed a new protection to address a vulnerability in React Server Components (RSC). All Cloudflare customers are automatically protected, including those on free and paid plans, as long as their React application traffic is proxied through the Cloudflare Web Application Firewall (WAF). Cloudflare Workers are inherently immune to this exploit. React-based applications and frameworks deployed on Workers are not affected by this vulnerability.