Vulnerability details

CVE-2026-84997

reactphp http

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

CVSS 3.1
7.5High

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

ScoreVersionSourceVector
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

VendorProductVersionsSource
reactphp http >= 0.6.0, < 1.11.1 CVEProject cvelistV5 (CNA)

References and advisories

3
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Details

Published
2026-09-16
Last updated
2026-09-16
State
Published
Assigner (CNA)
GitHub_M

Exploit prediction (EPSS)

0.65%
Probability of exploitation in 30 days
51.6%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
Yes
Exploitation
Proof of concept
Technical impact
Partial

Weaknesses (CWE)

  • CWE-835
    Loop with Unreachable Exit Condition ('Infinite Loop')