React Server Components (RSC) have introduced a hybrid execution model that expands application capabilities while increasing the potential attack surface.
Following earlier disclosures and fixes related to React DoS vulnerabilities, an additional analysis of RSC internals was conducted to assess whether similar denial-of-service risks remained.
This analysis identified a new denial-of-service (DoS) condition that, under specific circumstances, can render a React server unreachable.
Context
Previous reports showed that malformed requests could trigger excessive server-side computation during RSC rendering and serialization. While patches addressed the known attack patterns, it remained unclear whether these issues were isolated or indicative of broader weaknesses.
Technical Overview
The analysis focused on the following RSC code paths:
- Server Component request parsing
- Recursive resolution and payload generation
By evaluating server behavior when processing unexpected but syntactically valid inputs, an alternative execution path was identified in which server resources could be exhausted. This behavior is not covered by existing mitigations and could be abused to sustain a denial-of-service condition.
The issue was reported to the React security team. Due to the potential impact, exploitation details are not disclosed here.
Mitigation
While framework-level fixes are under review:
- Imperva customers are protected against this issue.
- Imperva’s Application Security solutions detect and block malicious request patterns that trigger abnormal server-side processing before vulnerable paths are reached.
Conclusion
This work highlights the importance of ongoing security evaluation of modern application architectures and the role of layered protections in mitigating denial-of-service conditions.
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