Package Instance

Next Vulnerable to Denial of Service with Server Components
A vulnerability affects certain React packages for versions 19.0.0, 19.0.1, 19.1.0, 19.1.1, 19.1.2, 19.2.0, and 19.2.1 and frameworks that use the affected packages, including Next.js 15.x and 16.x using the App Router. The issue is tracked upstream as [CVE-2025-55184](https://www.cve.org/CVERecord?id=CVE-2025-55184).

A malicious HTTP request can be crafted and sent to any App Router endpoint that, when deserialized, can cause the server process to hang and consume CPU. This can result in denial of service in unpatched environments.

Next.js Allows a Denial of Service (DoS) with Server Actions
### Impact
A Denial of Service (DoS) attack allows attackers to construct requests that leaves requests to Server Actions hanging until the hosting provider cancels the function execution.

_Note: Next.js server is idle during that time and only keeps the connection open. CPU and memory footprint are low during that time._

Deployments without any protection against long running Server Action invocations are especially vulnerable. Hosting providers like Vercel or Netlify set a default maximum duration on function execution to reduce the risk of excessive billing.

This is the same issue as if the incoming HTTP request has an invalid `Content-Length` header or never closes. If the host has no other mitigations to those then this vulnerability is novel.

This vulnerability affects only Next.js deployments using Server Actions.

### Patches

This vulnerability was resolved in Next.js 14.2.21, 15.1.2, and 13.5.8. We recommend that users upgrade to a safe version.

### Workarounds

There are no official workarounds for this vulnerability.

### Credits

Thanks to the PackDraw team for responsibly disclosing this vulnerability.

Next.js Improper Middleware Redirect Handling Leads to SSRF
A vulnerability in **Next.js Middleware** has been fixed in **v14.2.32** and **v15.4.7**. The issue occurred when request headers were directly passed into `NextResponse.next()`. In self-hosted applications, this could allow Server-Side Request Forgery (SSRF) if certain sensitive headers from the incoming request were reflected back into the response.

All users implementing custom middleware logic in self-hosted environments are strongly encouraged to upgrade and verify correct usage of the `next()` function.

More details at [Vercel Changelog](https://vercel.com/changelog/cve-2025-57822)

Next.js: HTTP request smuggling in rewrites
## Summary
When Next.js rewrites proxy traffic to an external backend, a crafted `DELETE`/`OPTIONS` request using `Transfer-Encoding: chunked` could trigger request boundary disagreement between the proxy and backend. This could allow request smuggling through rewritten routes.

## Impact
An attacker could smuggle a second request to unintended backend routes (for example, internal/admin endpoints), bypassing assumptions that only the configured rewrite destination/path is reachable. This does not impact applications hosted on providers that handle rewrites at the CDN level, such as Vercel. 

## Patches
The vulnerability originated in an upstream library vendored by Next.js. It is fixed by updating that dependency’s behavior so `content-length: 0` is added only when both `content-length` and `transfer-encoding` are absent, and `transfer-encoding` is no longer removed in that code path.

## Workarounds
If upgrade is not immediately possible:
- Block chunked `DELETE`/`OPTIONS` requests on rewritten routes at your edge/proxy.
- Enforce authentication/authorization on backend routes per our [security guidance](https://nextjs.org/docs/app/guides/data-security).

Next has a Denial of Service with Server Components - Incomplete Fix Follow-Up
It was discovered that the fix for [CVE-2025-55184](https://github.com/advisories/GHSA-2m3v-v2m8-q956) in React Server Components was incomplete and did not fully mitigate denial-of-service conditions across all payload types.  As a result, certain crafted inputs could still trigger excessive resource consumption.

This vulnerability affects React versions 19.0.2, 19.1.3, and 19.2.2, as well as frameworks that bundle or depend on these versions, including Next.js 13.x, 14.x, 15.x, and 16.x when using the App Router. The issue is tracked upstream as [CVE-2025-67779](https://www.cve.org/CVERecord?id=CVE-2025-67779).

A malicious actor can send a specially crafted HTTP request to a Server Function endpoint that, when deserialized, causes the React Server Components runtime to enter an infinite loop. This can lead to sustained CPU consumption and cause the affected server process to become unresponsive, resulting in a denial-of-service condition in unpatched environments.

Denial of Service condition in Next.js image optimization
### Impact
The image optimization feature of Next.js contained a vulnerability which allowed for a potential Denial of Service (DoS) condition which could lead to excessive CPU consumption.

**Not affected:**
- The `next.config.js` file is configured with `images.unoptimized` set to `true` or `images.loader` set to a non-default value.
- The Next.js application is hosted on Vercel. 

### Patches
This issue was fully patched in Next.js `14.2.7`. We recommend that users upgrade to at least this version.

### Workarounds
Ensure that the `next.config.js` file has either `images.unoptimized`, `images.loader` or `images.loaderFile` assigned.

#### Credits
Brandon Dahler (brandondahler), AWS
Dimitrios Vlastaras

Next.js Vulnerable to HTTP Request Smuggling
### Impact
Inconsistent interpretation of a crafted HTTP request meant that requests are treated as both a single request, and two separate requests by Next.js, leading to desynchronized responses. This led to a response queue poisoning vulnerability in the affected Next.js versions.

For a request to be exploitable, the affected route also had to be making use of the [rewrites](https://nextjs.org/docs/app/api-reference/next-config-js/rewrites) feature in Next.js.

### Patches
The vulnerability is resolved in Next.js `13.5.1` and newer. This includes Next.js `14.x`.

### Workarounds
There are no official workarounds for this vulnerability. We recommend that you upgrade to a safe version.

### References
https://portswigger.net/web-security/request-smuggling/advanced/response-queue-poisoning

Next.js Denial of Service (DoS) condition
### Impact
A Denial of Service (DoS) condition was identified in Next.js. Exploitation of the bug can trigger a crash, affecting the availability of the server.

**This vulnerability can affect all Next.js deployments on the affected versions.**

### Patches
This vulnerability was resolved in Next.js 13.5 and later. We recommend that users upgrade to a safe version.

### Workarounds
There are no official workarounds for this vulnerability.

#### Credit
* Thai Vu of [flyseccorp.com](http://flyseccorp.com/)
* Aonan Guan (@0dd), Senior Cloud Security Engineer

Authorization Bypass in Next.js Middleware
# 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, we 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_)