reactphp http up to 1.11.0 ChunkedDecoder ChunkedDecoder.php handleData infinite loop

Summaryinfo

A vulnerability categorized as problematic has been discovered in reactphp http up to 1.11.0. This affects the function handleData of the file ChunkedDecoder.php of the component ChunkedDecoder. Executing a manipulation can lead to infinite loop. This vulnerability is tracked as CVE-2026-84997. The attack can be launched remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in reactphp http up to 1.11.0. It has been declared as problematic. This vulnerability affects the function handleData of the file ChunkedDecoder.php of the component ChunkedDecoder. The manipulation with an unknown input leads to a infinite loop vulnerability. The CWE definition for the vulnerability is CWE-835. The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. As an impact it is known to affect availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-84997 since 09/02/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

By approaching the search of inurl:ChunkedDecoder.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 1.11.1 eliminates this vulnerability.

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Productinfo

Type

• JavaScript Library

Vendor

• reactphp

Name

• http

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11.0

Website

• Product: https://github.com/reactphp/http/

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