Impact

There is a denial of service vulnerability in React Server Components.

React recommends updating immediately.

The vulnerability exists in versions 19.0.0, 19.0.1 19.1.0, 19.1.1, 19.1.2, 19.2.0 and 19.2.1 of:

- react-server-dom-webpack - react-server-dom-parcel - react-server-dom-turbopack

These issues are present in the patches published last week.

Patches

Fixes were back ported to versions 19.0.2, 19.1.3, and 19.2.2.

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 vulnerability. If your app does not use a framework, bundler, or bundler plugin that supports React Server Components, your app is not affected by this vulnerability.

References

See the blog post for more information and upgrade instructions.

Impact

Applications using Partial Prerendering through the Cache Components feature can be vulnerable to connection exhaustion through crafted POST requests to a server action. In affected configurations, a malicious request can trigger a request-body handling deadlock that leaves connections open for an extended period, consuming file descriptors and server capacity until legitimate users are denied service.

Fix

We now treat the header used for resuming Partial Prerendered requests as an internal-only header and strip it from untrusted incoming requests. This header should never be accepted directly from external clients.

Workarounds

If you cannot upgrade immediately, block requests that would be handled by Next.js if they contain the Next-Resume header at the edge.

Impact

There is an unauthenticated remote code execution vulnerability in React Server Components.

We recommend upgrading immediately.

The vulnerability is present in versions 19.0.0, 19.1.0, 19.1.1, and 19.2.0 of: react-server-dom-webpack react-server-dom-parcel react-server-dom-turbopack

Patches

A fix was introduced in versions 19.0.1, 19.1.2, and 19.2.1. 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 vulnerability. If your app does not use a framework, bundler, or bundler plugin that supports React Server Components, your app is not affected by this vulnerability.

References

See the blog post for more information and upgrade instructions.

Impact It is possible to bypass authorization checks within a Next.js application, if the authorization check occurs in middleware.

Patches For Next.js 15.x, this issue is fixed in 15.2.3 For Next.js 14.x, this issue is fixed in 14.2.25 For Next.js 13.x, this issue is fixed in 13.5.9 For Next.js 12.x, this issue is fixed in 12.3.5 For Next.js 11.x, consult the below workaround.

Note: Next.js deployments hosted on Vercel are automatically protected against this vulnerability.

Workaround If patching to a safe version is infeasible, it is recommend that you prevent external user requests which contain the x-middleware-subrequest header from reaching your Next.js application.

Credits

- Allam Rachid (zhero;) - Allam Yasser (inzo)

A denial of service vulnerability exists in Next.js versions with Partial Prerendering (PPR) enabled when running in minimal mode. The PPR resume endpoint accepts unauthenticated POST requests with the Next-Resume: 1 header and processes attacker-controlled postponed state data. Two closely related vulnerabilities allow an attacker to crash the server process through memory exhaustion:

1. Unbounded request body buffering: The server buffers the entire POST request body into memory using Buffer.concat() without enforcing any size limit, allowing arbitrarily large payloads to exhaust available memory.

2. Unbounded decompression (zipbomb): The resume data cache is decompressed using inflateSync() without limiting the decompressed output size. A small compressed payload can expand to hundreds of megabytes or gigabytes, causing memory exhaustion.

Both attack vectors result in a fatal V8 out-of-memory error (FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory) causing the Node.js process to terminate. The zipbomb variant is particularly dangerous as it can bypass reverse proxy request size limits while still causing large memory allocation on the server.

To be affected you must have an application running with experimental.ppr: true or cacheComponents: true configured along with the NEXTPRIVATEMINIMALMODE=1 environment variable.

Strongly consider upgrading to 15.6.0-canary.61 or 16.1.5 to reduce risk and prevent availability issues in Next applications.

Impact

There is a source code exposure vulnerability in React Server Components.

React recommends updating immediately.

The vulnerability exists in versions 19.0.0, 19.0.1 19.1.0, 19.1.1, 19.1.2, 19.2.0 and 19.2.1 of:

- react-server-dom-webpack - react-server-dom-parcel - react-server-dom-turbopack

These issues are present in the patches published last week.

Patches

Fixes were back ported to versions 19.0.2, 19.1.3, and 19.2.2.

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 vulnerability. If your app does not use a framework, bundler, or bundler plugin that supports React Server Components, your app is not affected by this vulnerability.

References

See the blog post for more information and upgrade instructions.

Impact

It was found that the fix to address CVE-2025-55184 in React Server Components was incomplete and does not prevent a denial of service attack in a specific case.

We recommend updating immediately.

The vulnerability exists in versions 19.0.2, 19.1.3, and 19.2.2 of:

- react-server-dom-webpack - react-server-dom-parcel - react-server-dom-turbopack

These issues are present in the patches published on December 11th, 2025.

Patches

Fixes were back ported to versions 19.0.3, 19.1.4, and 19.2.3.

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 vulnerability. If your app does not use a framework, bundler, or bundler plugin that supports React Server Components, your app is not affected by this vulnerability.

References

See the blog post for more information and upgrade instructions.