CVE-2026-23870Network attack vector

Unauthenticated server crash via crafted function requests

Published May 6, 2026 · Updated May 6, 2026

Denial of service in affected Meta React 19 Server Components packages allows remote attackers to crash servers via crafted HTTP requests. The public advisory identifies Server Function endpoints as the request locus but does not disclose which parser or resource-allocation operation mishandles the crafted input. Exposure requires server-side React and a framework, bundler, or plugin supporting React Server Components; successful requests can exhaust memory or CPU and interrupt the application.

CVSS severity7.5
High
EPSS probability1.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in affected Meta React 19 Server Components packages allows remote attackers to crash servers via crafted HTTP requests. The public advisory identifies Server Function endpoints as the request locus but does not disclose which parser or resource-allocation operation mishandles the crafted input. Exposure requires server-side React and a framework, bundler, or plugin supporting React Server Components; successful requests can exhaust memory or CPU and interrupt the application.

The record

CVE
CVE-2026-23870
Published
May 6, 2026
Updated
May 6, 2026
Vendor
Meta Platforms, Inc.
Product
react-server-dom-parcel
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 6, 2026CVE publishedPublication date reported by the CVE source.
  2. May 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=19.0.0 <=19.0.5
  2. Affected versionversion=19.1.0 <=19.1.6
  3. Affected versionversion=19.2.0 <=19.2.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Meta Platforms, Inc. · react-server-dom-parcelversion=19.0.0 <=19.0.5; version=19.1.0 <=19.1.6; version=19.2.0 <=19.2.5
Meta Platforms, Inc. · react-server-dom-turbopackversion=19.0.0 <=19.0.5; version=19.1.0 <=19.1.6; version=19.2.0 <=19.2.5
Meta Platforms, Inc. · react-server-dom-webpackversion=19.0.0 <=19.0.5; version=19.1.0 <=19.1.6; version=19.2.0 <=19.2.5

Published CVSS scores

7.5Facebook, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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