React Server Components have multiple Denial of Service Vulnerabilities

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-23864: 2.58% estimated exploitation activity in the next 30 days; percentile 85.24 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact It was found that the fixes to address DoS in React Server Components were incomplete and we found multiple denial of service vulnerabilities still exist in React Server Components. We recommend updating immediately. The vulnerability exists in versions 19.0.0, 19.0.1, 19.0.2, 19.0.3, 19.1.0, 19.1.1, 19.1.2, 19.1.3, 19.1.4, 19.2.0, 19.2.1, 19.2.2, 19.2.3 of: - react-server-dom-webpack - react-server-dom-parcel - react-server-dom-turbopack The vulnerabilities are triggered by sending specially crafted HTTP requests to Server Function endpoints, and could lead to server crashes, out-of-memory exceptions or excessive CPU usage; depending on the vulnerable code path being exercised, the application configuration and application code. Patches Fixes were back ported to versions 19.0.4, 19.1.5, and 19.2.4. If you are using any of the above packages please upgrade to any of the fixed versions immediately. If your app’s React code does not use a server, your app is not affected by this…

Published by the source

29 Jan 2026, 15:00 UTC

Last modified by the source

3 Feb 2026, 03:04 UTC

Source last checked

26 Oct 2026, 12:41 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-83fc-fqcc-2hmg

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-83fc-fqcc-2hmg

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# Patch Next advisory brief: CVE-2026-23864

Advisory: React Server Components have multiple Denial of Service Vulnerabilities
IDs: CVE-2026-23864, GHSA-83fc-fqcc-2hmg
Record: https://patchnext.com/advisories/cve-2026-23864 (revision 2, source checked 26 Oct 2026, 12:41 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: react-server-dom-turbopack 19.2.4, 19.1.5, 19.0.4; react-server-dom-parcel 19.2.4, 19.1.5, 19.0.4; react-server-dom-webpack 19.2.4, 19.1.5, 19.0.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm react-server-dom-turbopack: affected >= 19.1.0-canary-7130d0c6-20241212, < 19.1.5; >= 19.0.0, < 19.0.4; >= 19.2.0-canary-63779030-20250328, < 19.2.4; fixed in 19.0.4, 19.1.5, 19.2.4
- npm react-server-dom-parcel: affected >= 19.0.0, < 19.0.4; >= 19.1.0-canary-7130d0c6-20241212, < 19.1.5; >= 19.2.0-canary-63779030-20250328, < 19.2.4; fixed in 19.0.4, 19.1.5, 19.2.4
- npm react-server-dom-webpack: affected >= 19.2.0-canary-63779030-20250328, < 19.2.4; >= 19.1.0-canary-7130d0c6-20241212, < 19.1.5; >= 19.0.0, < 19.0.4; fixed in 19.0.4, 19.1.5, 19.2.4

## Suggested inspection (read-only)
- `npm ls react-server-dom-turbopack --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls react-server-dom-parcel --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls react-server-dom-webpack --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on react-server-dom-turbopack, react-server-dom-parcel, react-server-dom-webpack.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-83fc-fqcc-2hmg (OSV record GHSA-83fc-fqcc-2hmg lists affected ranges: npm react-server-dom-parcel >=19.0.0 =19.1.0-canary-7130d0c6-20241212 =19.2.0-canary-63779030-20250328 =19.1.0-canary-7130d0c6-20241212 =19.0.0 =19.2.0-canary-63779030-20250328 =19.2.0-canary-63779030-20250328 =19.1.0-canary-7130d0c6-20241212 <19.1.5…)
- Verified: https://github.com/advisories/GHSA-83fc-fqcc-2hmg (GitHub-reviewed advisory GHSA-83fc-fqcc-2hmg lists affected ranges: npm react-server-dom-parcel >=19.0.0 =19.1.0-canary-7130d0c6-20241212 =19.2.0-canary-63779030-20250328 =19.1.0-canary-7130d0c6-20241212 =19.0.0 =19.2.0-canary-63779030-20250328 =19.2.0-canary-63779030-20250328 =19.1.0-canary-7130d0c6-20241212 =19.0.0 <19.0.4)

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