Listen to this Post
A denial-of-service vulnerability exists within the React Server Components (RSC) rendering engine in affected versions. The flaw is triggered during the serialization of specially crafted Server Component trees that create a pathological rendering state. When React attempts to reconcile and serialize a malicious component that induces a circular reference or an infinite asynchronous boundary loop, the server-side rendering process enters a non-terminating state. This consumes excessive CPU cycles and memory, as the React reconciler cannot exit the rendering phase. The process blocks the Node.js event loop or exhausts worker pool resources in serverless environments, leading to complete service unavailability. The issue stems from insufficient cycle detection and interruptible yield points within the RSC stream serializer when handling complex, user-supplied component structures.
Platform: React
Version: 19.0.0-19.2.1
Vulnerability: Denial of Service
Severity: High
Date: Dec 11, 2025
Prediction: Patched Dec 11, 2025
What Undercode Say:
Analytics:
Check current React version npm list react grep -r "19.[0-2].[0-1]" package.json
How Exploit:
Attacker crafts malicious Server Component inducing infinite rendering loop via recursive async boundaries or circular component references, exhausting server CPU/memory.
Protection from this CVE:
Update to patched versions (19.0.2, 19.1.3, 19.2.2). Disable RSC if not used. Implement request timeouts and resource limits at the server/load balancer level.
Impact:
Server resource exhaustion, application downtime, degraded performance for all users.
🎯Let’s Practice Exploiting & Learn Patching For Free:
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
