Vulnerability details
CVE-2026-84997
react/http: A malformed HTTP chunked body can lead to a denial-of-service and peg the CPU
Official 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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 7.5High | 3.1 | CVEProject cvelistV5 (CNA) (GitHub_M) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| reactphp | http | >= 0.6.0, < 1.11.1 | CVEProject cvelistV5 (CNA) |
References and advisories
3- https://github.com/reactphp/http/commit/b6d4688790adf3797071fcf88a3fc4225f30486a x_refsource_MISC
- https://github.com/reactphp/http/releases/tag/v1.11.1 x_refsource_MISC
- https://github.com/reactphp/http/security/advisories/GHSA-x424-64qh-5j54 x_refsource_CONFIRM
Details
- Published
- 2026-09-16
- Last updated
- 2026-09-16
- State
- Published
- Assigner (CNA)
- GitHub_M
Exploit prediction (EPSS)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- Proof of concept
- Technical impact
- Partial
Weaknesses (CWE)
- CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')